[ubuntu-uk] help with cifs permissions, please

[Mac]

I'd be grateful for advice with a problem that's a bit beyond my level
of expertise.

I've been mounting a network drive using the following in /etc/fstab 
(commands all on a single line), as per the Ubuntu smbfs HowTo:

//severIP/public /media/nas smbfs
guest,uid=1000,iocharset=utf8,codepage=unicode,unicode 0 0
//severIP/public /media/nas smbfs
credentials=~/.smbcredentials,dmask=777,fmask=777 0 0

This has mostly worked fine.  But recently when manipulating lots of
image files I've been getting annoying samba timeouts that freeze the
system.  Web searches suggest this is an issue with samba, and the fix
is to use cifs.

So after reading cifs HowTos at

http://ubuntuforums.org/showthread.php?t=288534

and

http://ubuntuforums.org/showthread.php?t=293513

I now have /etc/fstab thus:

//serverIP/public /media/nas cifs 
credentials=/root/.smbcredentials,iocharset=utf8,file_mode=0777,dir_mode=0777 
0 0

(all on one line, of course; and the correct credentials file exists in 
/root/ and is chmoded 700 as per the HowTo)

Unfortunately, when I copy a directory from home to nas, I am not the
owner on the nas, and cannot delete the directory.

Directories I copy have the following properties on the nas:

drwxr-xr-x  2 35000 root    0 2007-08-10 09:18 test

I can't see how to resolve this.  I'd be grateful for suggestions.

TIA

Mac