Is it safe to bypass a battery?
Have you tried just running the device off your USB power without a battery? possibly with an electrolytic cap in place of the battery?

If this doesn't work when i wanted to have a wired wii mote, i just soldered a 5v to 3v SOT-223 LDO to the battery prongs (and some ceramic caps) and wired it to a USB cable. This is essentially what @Passerby is talking about with his Battery Eliminator.

Also like @Elliot Alderson said, don't short your battery terminals with a wire. If the device doesn't work because it cuts off the USB power if there is no battery, then you can simulate a load with a 1k through hole resistor to make it look like a battery is being charged.