Ok, bad news... this is DIY
1. Order joypad(s) from here: ($4.55 USD including shipping world wide ~ 3.5 EUR)
https://www.dealextreme.com/details.dx/sku.30530
Here is picture of the device:
2. Open the 5 screws behind the device (very small Phillips screws)
Inside the device there is 9 wires connected to circuit board These wires connect to DB9F connector in following order: (from pin 1 to 9) Red, White, Brown, Yellow, Blue, Black, Grey, Orange, Green.
I'm going to call these soldering pads with numbers 1-9 from left to right (When you look ship side so that the texts are right way around and pads away from you) The colors from left to right are: Gray, Blue, Brown, Yellow, Black, Green, Red, White, Orange.
3. Disconnect grey (pad 1), green (pad 6) and orange (pad 9) wires
4. Connect gray wire to pad 6
5. Connect green wire to pad 9
6. Cut the orange wire so that it can't contact anything
7. Use the cutted part of orange wire to connect pads 1 & 2 together
Result should look something like this:
8. Put the device back together (Look that the joystick cable goes right way... one side is round, other side is not)
Ta-daa!
Now button "B" is MSX button "A" and button "C" is MSX button "B" (Other extra buttons are not in use)
~NYYRIKKI
