Did not read the whole thread...here are some info may be useful,

1) there is a gui on emelfm2, install it and it allows, file copying and renaming, etc, all like windows explore type graphic user interface. install instruction here,

2) Midnight Commander would do the same tricks as 1), both emelfm2 and MC are very powerful filemanager with a simple text editor

Or sometimes, one can dl files to your window desktop and change names etc before transferring to your N900. I use openSSH and winSCP to take care things like this.
step by step here

bun