1. find a member or learn to solder your own "plugs" *as seen in the diy make your own interconnect thread
2. find a mini 3.5 plug that you want to terminate with... either right angle or straight should be fine
3. cut off old plug
4. prepare / strip wire
5. solder on new plug
6. finish and enjoy
that should be the rough outline... details of course should be filled in by careful soldering techniques.
*edit... i personally think your best bet would be to find a good...