I was going to say geo-grafting hasn't played well with Lux from what I've read around the web. Personally, if I add parts like that, it's easier and fool proof just to do it in a modeler. Bridging verticies and whatnot. 

Geografting is an exercise in patience at this stage, for me anyway :-/

crimsonworx.com; free ebooks and previews

I've bowed down to facebook: https://www.facebook.com/crimsonworx