backup a folder but exclude a certain file(s)?

Hi all,
So I’ve managed to make an Applescript to backup the entire contents of a folder, using the ‘backup’ function from Satimage. But now I need to make a script that EXCLUDES one ore more items from backup. The ‘backup’ function doesn’t appear to be capable of that, so it looks like I’ll have to use ‘duplicate’ or something. Probably it would work to just traverse the folder contents and have an IF statement check to see if each file is the excluded one.
But my knowledge of AS syntax is so lacking that even that would take a long time to figure out. Anyone have any hints or care to point me in the right direction? thanks,