You cut the wire.. You need a pretty powerful soldering iron that gets real hot and you can feed solder into the wire with the insulation around it. So once you strip it.. It comes out nice and compact. That's the best way to do it..
But if you have a soldering iron that doesn't get hot enough. You'll have to do the method which I mentioned and solder the wire after stripping it and cutting part of it off with wire snips that way you can fit it into the plug.