That has nothing at all to do with using a USB controller on the DS, or the DS as a controller per say. It is merely using a USB connector as a 5 pin connection to have access to the D-pad connections of the DS, nothing more. All you could do there is wire up 4 buttons to your USB connector and use them instead of the D-pad, or wire it up to some other controllers D-pad and use the DS D-pad instead but that's all, and soldering to the contacts like that ruins them anyway.