Cell background limitaons

From: budding designer :D


lo ppl again, im still working on my site will b up soon i promise. dan i was wondering on the limitations of setting files as cell bkgrounds. i wanted to set a flash animation as a cel bk ground so i could have the famous "sliver" effect. however this doesnt seem possible in dreamweaver nor frontpage. am i doing someting wrong? another option is to use an animated gif would that work? cheers in advance :D (i promise to click a few ads ;) )