What version of Acrobat?
Can you please share GetButtonIcon() source code? I'm having difficulty in adding button. Tried a lot, but couldnt get through.
static void *GetButtonIcon ()
icon = LoadBitmap (gHINSTANCE, MAKEINTRESOURCE(IDB_BITMAP1));
return (void *)icon;
IDB_BITMAP1 is a resource in your VS 2008 vcproj.
If you add the label BEFORE you add it to the toolbar it works. I've tested this using the Acrobat X SDK in both Reader X and 11.
So basically, move this line to AFTER you set the label.
AVToolBarAddButton(toolBar, toolButton, true, toolsSeparator);