Clearing external XML data

how must one do it, how do you unload the data you uploaded. I got this problem when doing the tutorial for thumbnail scrollers. I want to have seperate buttons that load different sets of images into the bar.
It works fine, but the old images stay there!
Any help would be MUCH appreciated. here is a previous post that no-one has answered about this same problem, code is located there…

Link to other thread…

Regards,
Nutmeg.