smb server access via ip address?

[Jack Howarth]

   I have some machine located behind a firewall that
have to access Windows file servers via the tcp/ip address
protocol. On MacOS X, I am able to easily do this with
a smb url of the form...

smb://username@serverdomainname/path/to/serverdirectory

however I can't seem to get this to work under Nautilus
in either FC2 or RH Enterprise 3. Does either support
accessing smb file shares through a tcp/ip protocol and
if so what is the correct form of the url to use in
Nautilus?
                            Jack