Ah, I get you. So I'm guessing that it will be doing some conversion style calculation between the pointWorld attribute and the shader colour property. Again because I have no real knowledge of using it I would only guess that you have to grab the output of this process and put that in the text file instead.
Is the pointWorld attribute an input connected to the shader property? If so then there might be a way to connect the output of that somewhere - but that brings you back to the same problem of where. All I can think of is to somehow code it so the output is stored in a matrix (array) and then the matrix is dumped to the text file.
Hmm, this is a bit more advanced than I thought but interesting nonetheless. I dont think I've got the time to delve into it deeply but if I get the chance I'll let you know.

Simon

p.s, if you have a real basic version of your connection set up then post the file here and I'll try and take a quick look to see if it is more straightforward