how to change bitmap in today screen plugin ?

I have a today screen plugin app. It works well.
i have this in my init function.

case WM_PAINT:

.....
//////////////////////// FMC BUTTON
hdcScreenBuffer = CreateCompatibleDC(hDC);
GetClientRect(g_hWnd,&rcClient);
// Load the bitmap from the resource
hBitmap = LoadBitmap(g_hInst, MAKEINTRESOURCE(IDB_MY_BITMAP));
// hBitmap = CreateBitmap(rcClient.right, rcClient.bottom,1,8,NULL);
hBmpOld = (HBITMAP) SelectObject(hdcScreenBuffer,hBitmap);
BitBlt(hDC,90,4,60,40,hdcScreenBuffer,0,0,SRCCOPY);
DeleteObject(SelectObject(hdcScreenBuffer,hBmpOld));
......

Now i want to change hBitmap (IDB_MY_BITMAP) to IDB_MY_BITMAP2 if some
internal event appear.
How can i do that ?

.