Ok. I figured it out myself, I guess.
Maybe someone can confirm that this is the "right" way of doing this.
- Create a "Event:Scripted" and bind it to event OMNI
- You then have all the information you need in arg1, arg2.... just like you have when handling COMBATLOG_EVENT_UNFILTERED yourself
- Do something like if (arg2 == "SPELL_AURA_REMOVED")....
- Dispatch an event
Or is there an easier way?