I got a bag of 4 circuit TRRS 3.5mm coaxial plugs from Mouser and I am a bit unsure of how to wire them. The plugs have the standard ground/sleeve that also acts as a strain relief when crimped over the wire, but they don't have the standard solder terminals inside. The terminal for the last ring is a very thin rectangular protrusion and the tip and first ring are "pins", one inside the other with dilectric in between. The amount of the metal exposed is very small and not easily soldered to. Any ideas on how to use these?