Hi;
I'm using an Icron USB extender (
www.icron.com). The 'at-the-telescope' end of the extender I'm using has 4 ports. One is for the 320E, another for the guide camera (Orion), and the third for the USB to serial (to communicate with the mount).
The Icron isn't cheap, but it works. It's basically 'transparent' to the computer. Once everything is plugged in the computer 'thinks' the USB ports are local.
I've had no problem with this so far.
I heard about a guy who used one of these so that he could be in his trailer with his computer while his telescope, camera, etc were on the field.
Good luck