How to put a png fading window in a parent window ??

#include <GDIPlus.au3>
#include <WinAPI.au3>
#include <WindowsConstants.au3>
#include <GuiConstantsEx.au3>

Opt("MustDeclareVars", 0)

_GDIPlus_Startup()
$hImage = _GDIPlus_ImageLoadFromFile("C:\Users\TheDaverMan\Pictures\button.png")
$hGUI = GUICreate("GUI", 750, 500, 192, 128)
$hGUI2 = GUICreate("", 500, 250, 0, 0, $WS_POPUP, BitOR($WS_EX_LAYERED, $WS_EX_TOPMOST, $WS_EX_TRANSPARENT));BitOR($WS_EX_MDICHILD, $WS_EX_TOPMOST))

;~ DllCall("user32.dll", "int", "SetParent", "hwnd", $hGUI2, "hwnd", $hGUI) ;   <=  if I put parent, I don't see the png

SetBitmap($hGUI2, $hImage, 125);alpha

GUISetState(@SW_SHOW, $hGUI)
GUISetState(@SW_SHOW, $hGUI2)

Sleep(5000)

Func SetBitmap($hgui, $hImage, $iOpacity)
    Local $hScrDC, $hMemDC, $hBitmap, $hOld, $pSize, $tSize, $pSource, $tSource, $pBlend, $tBlend

    $hScrDC = _WinAPI_GetDC(0)
    $hMemDC = _WinAPI_CreateCompatibleDC($hScrDC)
    $hBitmap = _GDIPlus_BitmapCreateHBITMAPFromBitmap($hImage)
    $hOld = _WinAPI_SelectObject($hMemDC, $hBitmap)
    $tSize = DllStructCreate($tagSIZE)
    $pSize = DllStructGetPtr($tSize)
    DllStructSetData($tSize, "X", _GDIPlus_ImageGetWidth($hImage))
    DllStructSetData($tSize, "Y", _GDIPlus_ImageGetHeight($hImage))
    $tSource = DllStructCreate($tagPOINT)
    $pSource = DllStructGetPtr($tSource)
    $tBlend = DllStructCreate($tagBLENDFUNCTION)
    $pBlend = DllStructGetPtr($tBlend)
    DllStructSetData($tBlend, "Alpha", $iOpacity)
    DllStructSetData($tBlend, "Format", 1)
    _WinAPI_UpdateLayeredWindow($hgui, $hScrDC, 0, $pSize, $hMemDC, $pSource, 0, $pBlend, $ULW_ALPHA)
    _WinAPI_ReleaseDC(0, $hScrDC)
    _WinAPI_SelectObject($hMemDC, $hOld)
    _WinAPI_DeleteObject($hBitmap)
    _WinAPI_DeleteDC($hMemDC)
EndFunc