Description of Problem:
You can read files located on an ftp server but
you can't modify them even if you have permission.

PS: I opened the file from the FTP vfs in Nautilus.

Steps to reproduce the problem:
1. Go to ftp://ftp.foo.bar in Nautilus
2. Open a text file with gedit
3. Modify it and save it.

Actual Results:
The file can't be saved.

Expected Results:
The file should be saved and the changes should be
uploaded to the ftp server.

How often does this happen? 
Always.

Additional Information:
I think you should look at how kate/kwrite do it
using kio_ftp in KDE.