Not sure about SCOM, but you can send off an SNMP trap using custom alerts as described in SOL3727:
https://support.f5.com/kb/en-us/solutions/public/3000/700/sol3727.html (
Click here
To trigger the alert, just enable logging in the iRule which has the LB_FAILED event:
when LB_FAILED {
whatever your action is
log local0. "Client [IP::client_addr] has hit LB_FAILED"
}
So then your custom alert would look something like:
alert LB_FAILED_NOTICE "Client (.*) has hit LB_FAILED" { sn
mptrap OID=".1.3.6.1.4.1.3375.2.4.0.500" }
That OID is made up as described in the SOL.
Denny