Check out the sources of FlashNG: both AllocBitmap() and BltBitmap() are used...
http://nogfx.free.fr/flashflash.c/AllocFlash() => AllocBitmap()
flash.c/MoveRect()=> BltBitmap()
Maybe the sources I released a year or so ago will finally become usefull for someone

Regards,
Leo.
PS: It will work on both RTG (P96/CGX) and AGA...