The Windows Event Log Monitor "Keywords" should allow for partial matching. Have you tried using just "sv" in that field and seeing if that limits the results to only the service accounts you're looking for? Another option would be to customize the "Locked out users" script to look for only service accounts that are locked out. I'm sure someone in the Script Lab would be able to assist you with that if you need assistance.
Another option depending how many service accounts you have would be to duplicate this component monitor for each service account, placing the full service account name within the keywords field.