PS2 gamepad with converter on PC

Hello there!

Today i bought a converter, to use my playstation pad with my PC. But i have a problem now:
The analoge buttons dont work, allthough the two sticks work fine. I tried MGS2 with it. If you push the fire button a bit Snak should aim with his gun, and if you push harder he should fie. But this dont work, if i push a bit nothing happens, if i push harder he fires without aiming.
Does anyone has an idea how too get these buttons beeing analog in games?

thanks for you help.

Well its not a problem with the pad. The problem is either with the converter or the software supporting it.

i think its the games themselves that cant read some of the buttons, ive got a PSX Adapter and in some games (N64 Emu) it wont detect all buttons even in some psx ones, but the sega/and snes work fine and so does GTA 3, Vice, San And., and Simpsons Hit and Run