gvfsd-sftp do not preserve file ownership on file modification operation

Problem overview:
When using gvfs-sftp connection to modify some remote files, editing remotely (with gedit, sublime, etc) then saving these files changes their user and group ownership on server.

Problem configuration:
- one desktop with Ubuntu 12.04.2 LTS and Unity desktop
  (3.2.0-39-generic #62-Ubuntu SMP Thu Feb 28 00:28:53 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux)
- one server width Ubuntu 12.04.2 LTS server
  (3.5.0-25-generic #39~precise1-Ubuntu SMP Tue Feb 26 00:11:13 UTC 2013 i686 i686 i386 GNU/Linux)
- one server directory with some files
  - directory permission : drwxrwx--- serverUser clientUser
  - files in this directory : -rw-rw---- serverUser clientUser
    (aka <perms> <user-owner> <group-owner>)

Problem reproduction:
1- Use Nautilus (3.4.2) to "Connect to server ..." from your desktop pc to your server pc using your ssh 'clientUser' credential (as mentioned above).
2- Browse to the above mentioned directory through Nautilus (from desktop client in the remote served directory)
3- Open a remote file for edition with gedit (or any other desktop editor, from nautilus or command line like gedit ~/.gvfs/...)
4- Edit and save file
5- Check file permission on server directory
6- the file ownership has changed to something like -rw-rw---- clientUser clientUser

Using vi (or vim) give an error at save time, but, the content is save succefully, permission are set to something -rw------- clientUser clientUser