Thanks Nick! it worked 
Good
OK, here are the reasons that you need to do this by hand:
1) Microsoft's SMB naming services are brain-dead, IMHO. They rely on a lot of network "chatter" to ensure that the machine list is (more or less) up to date.
2) With (1) clearly understood, the way that the SME needs to interact with other Windoze machines is to be a bully & say "I'm in charge, don't talk amongst yourselves, refer all name questions to me". It does this by being the browse master and, in many scenarios, the WINS server also.
A side-effect of (2) is that if another Linux (or more properly a Samba) machine appears & then disappears from the workgroup, the namespace isn't reaped automatically if its master browser priority is the same as or higher than your primary SME.