I have a tube part and a plug that fits flush into the tube in an assembly, and I'm trying to specify that the end face of the tube and the shoulder face of the plug should be welded together. I've tried different types of welds, with and without mates, and searched the knowledge base without finding anything useful so far. It looks like a seam weld is the one I should be using, from the preview picture. The following configuration (in attached image) gives me the error "For this type of weld, the contact faces of one component must not touch the contact faces of the other component." As far as I can tell, they're not. Anyone got any idea what I'm doing wrong? This is in SW2010 SP0, btw.