Update:
Wrote a test function in a client script:
public function EmitterSpec(input as String)
tokens as List of String
Tokenize(input, tokens)
CustomizeParticleSpec(tokens[1], "MeshFileName", tokens[2])
.
In an area, I created an instance of a surface emitter. With it selected, I can see the mesh it uses as a wireframe, and the particles come off it as they should.
I get the ID of it from the properties panel and use that in the above function call via the console to change the meshfilename. I then see the wireframe change to the new mesh outline, but the particle freeze and no longer update.
It seems the emitter is being stopped, or something. Any idea how to start it again?