CIFS permissions/shares work great, but FTP fails

I have the same problem. I have one share which is FTP enabled (and CIFS of course), and when uploading stuff to that share from an FTP client, I can't do anything with it through CIFS, when logging in with the regular username. I haven't tried logging in to the local network with the FTP user name yet (I use the same ID and pass for all who accesses the FTP). When logging in with an FTP client on the same LAN (with the FTP user name), I can do everything. It seems as if the FTP user name has become the admin of that share somehow. I don't have any groups configured on the ReadyNAS, only individual users.

Here is the setup for the FTP share (note that I have the Swedish UI, so the options might be sligthly differently worded in English than what I have written below):

One user account with password that is given to those who need access to the FTP share.

CIFS
Default access: Read/write

Restrictions to shared access
Everything unchecked except Allow guest access

Advanced CIFS permissions
Set permissions automatically for new files and folders: checked
Do not allow ACL changes that are more restrictive than this: checked
Group rights: Read/write
Rights for everyone: Read/write

Oplock: checked

FTP/S
Default access: Read/write
Everything else unchecked

Advanced options
Owner of share folder: <share name>
Group of share folder: nogroup
The three permissions options are all set to read/write.

Grant users who don't own the files privileges to change names and remove data: checked

I would like to have some kind of visual overview of which users have what kind of rights to what shares. Could be presented as a simple matrix. On the other hand it might not be possible for more advanced configurations.

Anyway, I guess my question would be: How do I grant the 'normal' users (not the FTP user) CIFS access to the FTP share permanently? We do have sometimes, not just if the FTP user has uploaded something to the FTP share, then we need to log in with the FTP user through an FTP client, even when being on the same LAN as the NAS. Viewing is allowed, but nothing else.