Trap Processor varbinds

Hello
actually i use the standard template in the message field for the traps:

Sa Trap trap received from $SourceMO(displayName) with SNMP Varbinds $*

Accordfing to : https://support.zoho.com/portal/manageengine/helpcenter/articles/how-to-configure-trap-message

I tried to change $* with $2 $3 :

Sa Trap trap received from $SourceMO(displayName) with SNMP Varbinds $7 $8

Because i would like to see only this two value in the message but i it seems not work , this is the message :

Sa Trap trap received from myserver01 with SNMP Varbinds sysUpTime.0: 26 days, 19 hours, 24 minutes, 20 seconds. , snmpTrapOID.0: .1.3.6.1.4.1.36807.1.20.1 , .1.3.6.1.4.1.36807.1.20.1: ,rule=High System Swap Utilization, state=ACTIVE, severity=HIGH, host=HOSTNAME, service=APPLIANCE, alarmid=347-1116-0005, policy=SA custom Host Monitoring Policy, stat=SystemInfo/Swap Utilization, value=58.3% time=December 6, 2016 1:51:54 PM UTC utc=1481032314669 ,

How i can have in message only values that i need ?
Regards
Franco