I thought the same, but apparently this isn't the case. As you can see at the discussion in Arch forums, OMV knew how to look for the drivers in the correct locations, perhaps because it was patched to do so --unfortunately I lack the knowledge to read the patches-- while all the other viewers didn't.
Of course that doesn't mean that it isn't a matter of properly configuring the X server. But as the matter affects two distributions (that I know of), I think it could be addressed by the viewers on their end.