#cs http://www.autoit.de/index.php?page=Thread&postID=161092#post161092
Functions:
Scrollbar_Create($hWnd, $iBar, $iMax)
Scrollbar_Scroll($hWnd, $iBar, $iPos)
Scrollbar_GetPos($hWnd, $iBar)
Scrollbar_Step($iStep, $hWnd=0, $iBar=0)
#CE

#Include <GuiScrollBars.au3>
#include<GuiconstantsEx.au3>
#include<WindowsConstants.au3>
#include <ScrollBarConstants.au3>

Global $SCROLL_AMOUNTS[1][3]
$SCROLL_AMOUNTS[0][0] = 1
func Scrollbar_Create($hWnd, $iBar, $iMax)

    Local $Size = WinGetClientSize($hWnd)

    If $iBar = $SB_HORZ Then
        $Size = $Size[0]
    ElseIf $iBar = $SB_VERT Then
        $Size = $Size[1]
    Else
        Return 0
    EndIf

    ReDim $SCROLL_AMOUNTS[UBound($SCROLL_AMOUNTS)+1][3]
    $SCROLL_AMOUNTS[UBound($SCROLL_AMOUNTS)-1][0] = $hWnd
    $SCROLL_AMOUNTS[UBound($SCROLL_AMOUNTS)-1][1] = $iBar
    $SCROLL_AMOUNTS[UBound($SCROLL_AMOUNTS)-1][2] = $SCROLL_AMOUNTS[0][0]

    _GUIScrollBars_EnableScrollBar($hWnd, $iBar)
    _GUIScrollBars_SetScrollRange($hWnd, $iBar, 0,$iMax-1)
    _GUIScrollBars_SetScrollInfoPage($hWnd, $iBar, $Size)

    GUIRegisterMsg($WM_VSCROLL, "WM_VSCROLL")
    GUIRegisterMsg($WM_HSCROLL, "WM_HSCROLL")

    Return $iMax

EndFunc
Func Scrollbar_GetPos($hWnd, $iBar)

    Local $tSCROLLINFO = _GUIScrollBars_GetScrollInfoEx($hWnd, $iBar)

    Return DllStructGetData($tSCROLLINFO, "nPos")

EndFunc
Func Scrollbar_Scroll($hWnd, $iBar, $iPos)

    Local $tSCROLLINFO = _GUIScrollBars_GetScrollInfoEx($hWnd, $iBar)

    $iCurrentPos = DllStructGetData($tSCROLLINFO, "nPos")

    DllStructSetData($tSCROLLINFO, "nPos", $iPos)
    DllStructSetData($tSCROLLINFO, "fMask", $SIF_POS)
    _GUIScrollBars_SetScrollInfo($hWnd, $iBar, $tSCROLLINFO)

    If $iBar = $SB_VERT Then

        $iRound = 0

        for $i = 1 to UBound($SCROLL_AMOUNTS)-1
            If $SCROLL_AMOUNTS[$i][0] = $hWnd And $SCROLL_AMOUNTS[$i][1] = $SB_VERT Then
                $iRound = $SCROLL_AMOUNTS[$i][2]
            EndIf
        Next

        If Not $iRound Then Return 0

        _GUIScrollBars_ScrollWindow($hWnd, 0, Round(($iCurrentPos-$iPos)/$iRound)*$iRound)
    ElseIf $iBar = $SB_HORZ Then

        $iRound = 0

        for $i = 1 to UBound($SCROLL_AMOUNTS)-1
            If $SCROLL_AMOUNTS[$i][0] = $hWnd And $SCROLL_AMOUNTS[$i][1] = $SB_HORZ Then
                $iRound = $SCROLL_AMOUNTS[$i][2]
            EndIf
        Next

        If Not $iRound Then Return 0

        _GUIScrollBars_ScrollWindow($hWnd, Round(($iCurrentPos-$iPos)/$iRound)*$iRound, 0)
    Else
        Return 0
    EndIf

    Return 1

EndFunc
Func Scrollbar_Step($iStep, $hWnd=0, $iBar=0)

    If not $hWnd or Not $iBar Then

        $SCROLL_AMOUNTS[0][0] = $iStep
        Return 1

    EndIf

    $iID = 0

    for $i = 1 to UBound($SCROLL_AMOUNTS)-1
        If $SCROLL_AMOUNTS[$i][0] = $hWnd And $SCROLL_AMOUNTS[$i][1] = $iBar Then
            $iID = $i
            ExitLoop
        EndIf
    Next

    If Not $iID Then Return 0

    $SCROLL_AMOUNTS[$iID][2] = $iStep

    Return 1

EndFunc
Func WM_VSCROLL($hWnd, $Msg, $wParam, $lParam)

    #forceref $Msg, $wParam, $lParam
    Local $nScrollCode = BitAND($wParam, 0x0000FFFF)
    Local $index = -1, $yChar, $yPos
    Local $Min, $Max, $Page, $Pos, $TrackPos
    ; Get all the vertial scroll bar information
    Local $tSCROLLINFO = _GUIScrollBars_GetScrollInfoEx($hWnd, $SB_VERT)
    $Min = DllStructGetData($tSCROLLINFO, "nMin")
    $Max = DllStructGetData($tSCROLLINFO, "nMax")
    $Page = DllStructGetData($tSCROLLINFO, "nPage")
    ; Save the position for comparison later on
    $yPos = DllStructGetData($tSCROLLINFO, "nPos")
    $Pos = $yPos
    $TrackPos = DllStructGetData($tSCROLLINFO, "nTrackPos")

    $iRound = 0

    for $i = 1 to UBound($SCROLL_AMOUNTS)-1
        If $SCROLL_AMOUNTS[$i][0] = $hWnd And $SCROLL_AMOUNTS[$i][1] = $SB_VERT Then
            $iRound = $SCROLL_AMOUNTS[$i][2]
        EndIf
    Next

    if Not $iRound Then Return $GUI_RUNDEFMSG

    Switch $nScrollCode
        Case $SB_TOP ; user clicked the HOME keyboard key
            DllStructSetData($tSCROLLINFO, "nPos", $Min)
        Case $SB_BOTTOM ; user clicked the END keyboard key
            DllStructSetData($tSCROLLINFO, "nPos", $Max)
        Case $SB_LINEUP ; user clicked the top arrow
            DllStructSetData($tSCROLLINFO, "nPos", $Pos - $iRound)
        Case $SB_LINEDOWN ; user clicked the bottom arrow
            DllStructSetData($tSCROLLINFO, "nPos", $Pos + $iRound)
        Case $SB_PAGEUP ; user clicked the scroll bar shaft above the scroll box
            DllStructSetData($tSCROLLINFO, "nPos", $Pos - $Page)
        Case $SB_PAGEDOWN ; user clicked the scroll bar shaft below the scroll box
            DllStructSetData($tSCROLLINFO, "nPos", $Pos + $Page)
        Case $SB_THUMBTRACK ; user dragged the scroll box
            DllStructSetData($tSCROLLINFO, "nPos", Round($TrackPos/$iRound)*$iRound)
    EndSwitch

;~    // Set the position and then retrieve it.  Due to adjustments
;~    //   by Windows it may not be the same as the value set.
    DllStructSetData($tSCROLLINFO, "fMask", $SIF_POS)
    _GUIScrollBars_SetScrollInfo($hWnd, $SB_VERT, $tSCROLLINFO)
    _GUIScrollBars_GetScrollInfo($hWnd, $SB_VERT, $tSCROLLINFO)
    ;// If the position has changed, scroll the window and update it
    $Pos = DllStructGetData($tSCROLLINFO, "nPos")


    If ($Pos <> $yPos) Then
        _GUIScrollBars_ScrollWindow($hWnd, 0, $yPos - $Pos)
    EndIf
    Return $GUI_RUNDEFMSG
EndFunc   ;==>WM_VSCROLL
Func WM_HSCROLL($hWnd, $Msg, $wParam, $lParam)

    #forceref $Msg, $wParam, $lParam
    Local $nScrollCode = BitAND($wParam, 0x0000FFFF)
    Local $index = -1, $yChar, $yPos
    Local $Min, $Max, $Page, $Pos, $TrackPos
    ; Get all the vertial scroll bar information
    Local $tSCROLLINFO = _GUIScrollBars_GetScrollInfoEx($hWnd, $SB_HORZ)
    $Min = DllStructGetData($tSCROLLINFO, "nMin")
    $Max = DllStructGetData($tSCROLLINFO, "nMax")
    $Page = DllStructGetData($tSCROLLINFO, "nPage")
    ; Save the position for comparison later on
    $yPos = DllStructGetData($tSCROLLINFO, "nPos")
    $Pos = $yPos
    $TrackPos = DllStructGetData($tSCROLLINFO, "nTrackPos")

    $iRound = 0

    for $i = 1 to UBound($SCROLL_AMOUNTS)-1
        If $SCROLL_AMOUNTS[$i][0] = $hWnd And $SCROLL_AMOUNTS[$i][1] = $SB_HORZ Then
            $iRound = $SCROLL_AMOUNTS[$i][2]
        EndIf
    Next

    if Not $iRound Then Return $GUI_RUNDEFMSG

    Switch $nScrollCode
        Case $SB_TOP ; user clicked the HOME keyboard key
            DllStructSetData($tSCROLLINFO, "nPos", $Min)
        Case $SB_BOTTOM ; user clicked the END keyboard key
            DllStructSetData($tSCROLLINFO, "nPos", $Max)
        Case $SB_LINEUP ; user clicked the top arrow
            DllStructSetData($tSCROLLINFO, "nPos", $Pos - $iRound)
        Case $SB_LINEDOWN ; user clicked the bottom arrow
            DllStructSetData($tSCROLLINFO, "nPos", $Pos + $iRound)
        Case $SB_PAGEUP ; user clicked the scroll bar shaft above the scroll box
            DllStructSetData($tSCROLLINFO, "nPos", $Pos - $Page)
        Case $SB_PAGEDOWN ; user clicked the scroll bar shaft below the scroll box
            DllStructSetData($tSCROLLINFO, "nPos", $Pos + $Page)
        Case $SB_THUMBTRACK ; user dragged the scroll box
            DllStructSetData($tSCROLLINFO, "nPos", Round($TrackPos/$iRound)*$iRound)
    EndSwitch

;~    // Set the position and then retrieve it.  Due to adjustments
;~    //   by Windows it may not be the same as the value set.
    DllStructSetData($tSCROLLINFO, "fMask", $SIF_POS)
    _GUIScrollBars_SetScrollInfo($hWnd, $SB_HORZ, $tSCROLLINFO)
    _GUIScrollBars_GetScrollInfo($hWnd, $SB_HORZ, $tSCROLLINFO)
    ;// If the position has changed, scroll the window and update it
    $Pos = DllStructGetData($tSCROLLINFO, "nPos")


    If ($Pos <> $yPos) Then
        _GUIScrollBars_ScrollWindow($hWnd, $yPos - $Pos, 0)
    EndIf
    Return $GUI_RUNDEFMSG
EndFunc   ;==>WM_HSCROLL