@webwit
The datahand looks too expensive for me I am afraid. But thanks for the tip it gives me hope

@FKSSR
I use autohot key to send my keyboard signals all over the place, I multibox on WoW.
I can't see how a software solution can do this, the KVM is dumb, it only detects the hard signal at the keyboard designated usb port.
No use the computer converting the a hard signal at a software level, its too late by then, it's already passed through the kvm.
Unless I could get the computer to pretend it is a keyboard plug it into the input of the KVM and send a signal out over the usb. But I haven't a clue how to make a computer send a keystroke out through a usb port. Autohot keys uses the network to pass out the keyboard commands.
As far as I can see I think I need a hardware solution