I looked last version of catweasel driver for Amiga and you are sure. It says that works with Mediator:
" This device is prepared to support the Catweasel MK3
in a PCI slot of an emulated Amiga (Amithlon, Amiga Forever
and the like), and Amiga PCI daughterboards like G-Rex,
Mediator and Prometheus. It still supports all versions of
the Catweasel since fall 1996."
I will try to use it tomorrow with OpenPCI and Catweasel MK IV Plus.
[]s
That last version of OpenPCI works just fine with the Mediator, and I'm pretty sure the last version of multidisk.device for the Catweasel supports OpenPCI on the Mk3. I think the Mk4 is supported as well, but you might want to check with Jens to verify.