It seems to me that OFED 1.5.1 has been released. I'd recommend to use the latest one because the newest version has some bug fixes which can be quite important for you. In release notes you can see that OFED supports Voltaire switches but there is no information about exact model.
Intel MPI Library reads /etc/dat.conf line by line and tries to use the first available device. If don't want to use for example the first device you can just comment ('#') the first line in dat.conf and iMPI will not try to use it.