Does anyone know whether the GXR is able to work with any other cable remote aside from the Ricoh CA-1?

I've got the Cactus V5 RF transceivers which can trigger the shutter remotely though use of an appropriate remote interface cable. If the plug type and switching pin-out of the GXR is the same as some other brand and model camera, it will be easy ... otherwise, I'll have to do some creative wiring.

thanks in advance. :-)