Yepp, i have done it exactly this way and it works..

Almost...
When i have alot of colours on the screen and then draw my rectangle the background changes to another colour instead of preserving the original, even though i've set it as in the autodocs, for all planes like this...
BltBitMap(srcbmp,srcx,srcy,dstbmp,dstx,dsty,width,height,0xC0,0xFF,NULL);
This should ensure that all planes should be copied shouldn't it?
Note i run this through WinUAE since my std amiga doesn't allow higher rez than 640*480..
Any ideas?