Rename only presents, for what I see as my access. the title I gave it.
Do you mean that your filenames don't show the extension .zip, .cbz, etc?
In that case you should open in one of the menus over the window (tools menu?)
folder options --> see configuration --> uncheck "hide file extensions...."
I don't know exactly the English menu names because I am using an Spanish edition of Windows XP.
You should be able to see the file extensions file.zip or whatever, and then clicking on the file names
you can rename. If you cannot, then to open the zip file with CDisplay, just do
right click --> open with --> choose CDisplay from the list of programs
It is also OK if you send by ftp just the zip file