As far as I know the PS2/USB adapter contains no active components - just wires.
Provided the USB mouse/keyboard states that it is PS2 compatible, then it will work with the PS2/USB adapter.
The statement will be found on a sticker on the underside of the mouse/keyboard and will read something like "PS2 & USB compatible". If it's not stated - chances are it won't work with a PS2 adapter.
I've built both PS2M and IBMkey adapters and have had no problems running (PS2 compatible) USB mice and keyboards.
