Third party disks for Ultrix

[Hugh LaMaster]

We have a VAX 11/785 running 2.2, with a UDA-50 and two ra81's,
and two SI drives (RM05 look alikes I think) using an SI Massbus
controller (I think).

Question:  does anyone have any experience with using anything
like an Emulex SBI controller and CDC or Fujitsu disks on Ultrix?

If so, are the controller and disks DEC lookalikes (Do you need
a new driver or can you use an existing one for an RM05, say)?
(My ignorance is showing, but if anyone knows where to start 
looking for more information, I would appreciate it).