I am trying to run the following query (FB 2 RC3):

SELECT distinct ROWID FROM events
WHERE events.ROWID IN (

SELECT DISTINCT DESTINATION.EVENTID FROM DESTINATION
WHERE ( (DESTINATION.IP ='158.125.73.220'))
)

The default plan that is used is:
PLAN SORT ((DESTINATION INDEX (IDX_DESTINATION2, IDX_DESTINATION1)))
PLAN SORT ((SEAM_EVENT NATURAL))

where IDX_DESTINATION2, IDX_DESTINATION1 are indexes on
DESTINATION.EVENTID and DESTINATION.IP respectively.

This plan is very ineffecient since the plan does not rely on the
index for events.ROWID. When I try to use a customized plan with this
index, FB replies that the index cannot be used in this query.

Is there anything else that can be done (except for using INNER JOIN)?
Why can't FB use the indexes on the events table?

Thanks.