Problems with Unix -windows name translation

I want to maintain some .qmail files on a windows PC but cannot transfer them from the host - the filenames mandatorily must contain a : symbol which is not permitted under the other (braindead) operating system. I couldnt find any option to translate filenames to acceptable character ranges - for instance using the %xx syntax that web browsers use - I dont really want to rename them at the Unix end either. Any suggestions?
The program is of course great....