Go to Welfare Electronics in Apliu Street, in the 1/f they have electronics components. Buy connectors and wires, and make it by yourself. If you don't have what it takes to make it, ask them to quickly put it together for you. If they don't do it, I am sure they can point you at the right direction (one of the mobile phone repair shops downstairs maybe).
WECL Online
Thinking of it, they may actually have something like this lying around. Maybe with more wires/pins, just cut it down in this case.
It also reminds me of the audio cable that comes with CD-ROM drives (haven't installed one of those for like 6 years or so) and goes from the CD-ROM drive to the mainboard of the computer (to output CD audio). CD-ROM drives are cheap, maybe you can pick up a brand new one for a hand full of dollars nowadays. There is also a second hand and "ancient parts" computer store on Apliu Street when you walk from the MTR exit towards the road with Dragon Center, on the right side. Maybe you can pick up a CD-ROM drive there.
Sun Cheung Computer Co or one of the adjacent shops:
http://maps.google.com/maps?q=apliu+...,45.08,,0,6.52