I am currently waiting on my Vetra 4-port PS/2 multicaster, but I have been programming my PS/2 X-Keys on my main machine, which has a usb keyboard, with no trouble. As has been said, you will need a PS/2 keyboard to plug into the X-Keys to program it. I plan on keeping it plugged in so that I can easily have a keyboard being broadcasted alongside the programmed X-keys should I ever need it.

I have not yet attempted anything using Vetra's USB multicasters since the PS/2 seems to be far more reliable. In the future, I plan on using the Vetra USB multicaster (which, according to them, works well) to broadcast a mouse. Usually, I'm playing a different class or spec on my main machine, so the 4-port multicasters are just fine for me.

It seems that we're still waiting on someone with USB multicaster experience to pipe up.