Real-time change ControlId_551 BITMAP

[prtec_tw]

I want to change Bitmap real-time

I write an MFC application.

HBITMAP bitmap = (HBITMAP)LoadImage(NULL,"c:\\aa.bmp", IMAGE_BITMAP,0,0,LR_LOADFROMFILE);
::SendMessage(hWnd,STM_SETIMAGE, (WPARAM)IMAGE_BITMAP,(LPARAM)bitmap);


hWnd i use spy to find "ControlId_551" HWND,but it still not success.

any body can help me???

[prtec_tw]

i repleace this file "Script\Dialogs\BitmapId_103.bmp" but
the bitmap still not change .

I use IS2010 Premier . Is this new Bug?????