DEC RM05 mountings

Does anyone know how an RM05 drive assembly fastens to the massbus control cab beneath? Doesn't seem likely that the drive assembly just rests on top - but there's no obvious way of securing the drive/cab together. I assume something's supposed to thread through the bracket at the top-front of the control cab and attach to the drive, but what/how? And then what secures the drive toward the rear? We almost got out Decsystem 570 completely rebuilt yesterday (it was totally dismantled and parts have been spread everywhere for the last few years) - just got the battery backup units and comms brackets to bolt on, and a couple of minor bits of trim to find and it's done. I'd stick some pictures up somewhere but I've just realised I have no idea how to get them off the camera with this new version of linux - d'oh! :-) cheers, Jules