How do I mount an SMB folder as Guest?

I have a NAS using a fixed local IP (192.168.0.18) and I want to mount one of the folders ('Shared') via Applescript as a Guest

I have set-up the folder to accept Guest users, but if I use:

Mount Volume "smb://192.168.0.18/Shared/"

..I get prompted to logon (so I then click 'Guest' and login, but I don't want to)

Obviously:

Mount Volume "smb://Guest@192.168.0.18/Shared/"

...doesn't work because it then opens the logon prompt with Guest as the username.

Any ideas?

Thanks!