http://peccatte.karefil.com/software/MacNames/MacNamesEN.htm Here is a utility. Another little weird thing I stumbled across was a thread that said that if a mac user saves a files to his desktop and not to documents first then Pc's cant read it.
You might want to look at AdmitMac and/or Dave if the problem still persits. I think it is valid replacement for a Widows designed interface. http://www.thursby.com/