Once you've reached this key you need to look for the sub-key beneath with the information about your own gamepad. Mine for example appears under VID_0B43&PID_0003.
On the right-hand side of the registry you will notice a key named OEMName. If you there isn't a OEMName. Right-click on the RHS and select New then String Value. Type in OEMName. Now you can enter the name of a "supported" controller. The name you use is sometimes dependant on the type of pad you have. In my OEMName I changed it to: