psp replacement nub + ps2 controller?

[neverused]

I have three psp replacement nubs from dealextreme, one extra just in case, and I am trying to figure out how to use one of those to replace the analog stick on a ps2 controller. Is this possible? I found this guide on engadget and tried doing the exact same thing, just backwards, but when I did, it didn't work and one of the connections got really hot, so I stopped that right away. Can anyone help me with this? I plan to use the psp nubs in a ps2 portable if possible, but if I can't hook them up, I can't use them. Thanks.