Kevin Holman has written an excellent article on the murkey subject of SNMP Trap monitoring with SCOM 2012 R2. This is definitly worth a read if you’ve ever been unclear on how this works.
It’s also nice to know once and for all “First clarification (and update to this blog post) – There is NO NEED to install or configure the SNMP service on the management server. We don’t use the SNMP stack. In fact – if the SNMP TRAP service is running (it does not by default) then only thing I need to do is make sure it is disabled! “
He has also kindly included MP authoring examples which you can use to get this running for your own scenarios.