BBain,
I've never had a mouse working in it. I lack the actual converter to do it with a serial mouse mind. Technically if it would work you could do it with a PS2 ball mouse with a serial changer and then the changer from the end of the sync cable to the mouse.
I have though never seen anyone having success in getting it to work so I've not pursued it.
PS,
my z50 doesn't have USB on it. to my knowledge none of them do.
If you're in doubt on a H/PC device, look it up on our device list first
http://www.hpcfactor.com/hardware/devices/
EDIT: I just went and had a rake about in my gender changer bag.
(... does that sound kinky
). I don't have the required converter. So I cannot be more specific to you.
Again though, I've never seen reference to or been contacted by anyone who has done it with a z50.