you can not directly generate an SNMP-trap out out events already in the cell.
If you want to do that you'll have to write a small script that calls a external tool to generate the trap (eg the one from net-snmp).
That script can be called out the rules via an "execute" statement. You can additionally define the script as an action, so that that action can be invoked from the IX in context of an event.
Hope it helps,