I can't take credit for this, it was in someone's write-up, but it should be added to the gamepad's FAQ (hint, hint)
A picture would be worth ten-thousand words now, but I'll try. Most gamepad's have a circular contact under the buttons with some "fingers" on one trace and interlocking fingers on the other trace.
Here's what you do - Come in with a Dremel (about $40.00 or Wal-Mart has a generic for $20 and about $6 for the accessories (I have the generic)) and the abrasive wheel attachment and cut perpendicular to the two traces and all the way across the contact pad. Don't cut through the board, but cut enough to break any electrical contact between the fingers.
Example explanation again - Before cut - Trace comes in from north with 6 fingers that extend to south portion of circle. Second trace comes in from south with 6 fingers that extend to north portion of circle. Make east-west cut through circle with Dremel.
What you end up with is an upper half circle with 6-half fingers that connect to the upper trace, and 6 half-fingers that are not connected electrically to anything. And a lower half-circle with 6 half-fingers that connect to the lower trace and six half-fingers that are not connected to anything.
What this means is you can lay an 1/8-inch glob of solder down and not worry about shorting the traces together. (I still think it's a good idea to drill holes to attach the wires to, but you can be a lot sloppier in where you drill and how you solder now.)
Hope this helps!!!!