How to have an external with a dotted name on windows?

Yet another windows dev question: I have figured out my issues were stemming from VS project settings. I seem to be unable to make a windows external with a dot in it's name, though presumably it's possible, because node.script exists. I can do this fine on xcode. However, if I make a VS project and solution named s4m.scm, and ensure the call to class_new uses that name, I get an object, but it errors on load. If I change all those back to just "s4m", no issues. Anyone know how to make this work on windows? Or do i need to change the name of the external? :-/