yeah...except there is no hacking the cable since you are using the adaptaplugs.
here's how i did mine...rather unscientifically:
take the adaptaplug cable and fold it in half so the two striped cables are adjacent/touching and with both adaptaplug "ends" pointing up.
then put the "M" adapta plug on one side, and the "B" adaptaplug on the other side so both connectors are facing you. (you should be looking into to small circles at this point)
(NOTE...the positive side on the "B" should be the negative on the "M" plug...or vice versa...shouldnt matter...just make sure both striped cable halves are touching)
plug the B plug into the battery out....test for continuity...or just plug the M plug into the ua-5 and see if it works...
if all is well than charge the battery up to full and you are golden, pony boy
disclaimer...I am NOT responsible if you f*ck up and sizzzle your gear!