[Zope] Applying fmt rules to variables

Hi all, I have an old system Im migrating that makes use of images that are kept in numbered directories. The mehtod they were saved before required that the whitespace in the names had a +. In other words, something like <dtml-var name url_quote_plus> BUT, I need to actually save these files, and the above formatting rule only seems to be applyable to output. How can I do something like <dtml-call "REQUEST.set('name', lname fmt=url_quote_plus)"> I know thats obviously NOT how to do it, but Im wondering at this point if it is at all, or do I have to rename all 600 files to not use +? I guess, first would be to do a string search and replace, but Im not sure where to start.... Cheers, Paz