Fixes Bug 1072540 - Look Ma! No pipe dump!

the TransformRule version of the stackwalker invocation without producing or needing a pipe dump!  
This is a strange comment. Is it some sort of excuse :) Is the code now good? 

Either way, I think all this preprocessing of the parameters could be refactored into a little private method or something with a comment that explains why it's necessary and what the quirks might be.