KVM Switch - PS2 and SUN

I have a dilemma regarding KVM switches. I need to be able to connect an old SUN ULTRA 10 to a KVM in order to switch between it and a normal (PS/2) PC. The trouble is, the SUN box uses proprietary connections (13W3 (video) and DIN8 (keyboard/mouse)).

The problem lies in that I need to be able to use the SUN peripherals for the console, meaning I need to be able to use the SUN keyboard and mouse to control both boxes. The SUN monitor has a seperate VGA input, so that is not a problem.

I have seen the Belkin SUN->PS/2 converter box, but in sketching out the details, it turns out this will not work, as the converter box would convert the keyboard signals to PS/2, but then there would be nothing to convert the signal back to connect the SUN box to the switched side.

Has anyone ever had to do this before, and if so what was the solution? Any recommendations for SUN and PS2 switches that can do this? Thanks in advance for your help.