whats the trick to installing new engine mounts???

My son got a VS ute and asked me to take it in for a RWC as he thought he had fixed everything the only thing that he missed was the RH engine mount so I picked one up at the local parts store .As my son is working in Melbourne I thought Id drop it in for him the bloke behind the counter told me the were a bit of a bugger .After mucking around for 2 hours I still haven't got the dam thing in 5 min to drop it out but cant seem to get the new ones holes to line up .(I did check if they were the same)

anyone got any pointers

Thanks