Edit uploaded file or Set path of new upload

We have a MultiUser environment where most blog owners/authors don’t have FTP access to the server.

My issue is the following situation:
In January, a user uploads an attachment and it ends up in:
[…]/2010/01/document.txt

In February, they want to change that document. I currently see no way to get the document at the same url as the original txt file. They can’t edit the file directly. They can’t overwrite it (no ftp access). The closes they can do is upload a new version, but it will be forced to be at:
[…]/2010/02/document.txt

is there ANY way, sans ftp, that will let the user edit or replace the document *at the same url* ?

Thanks in advance!