Unless you are saying you are looking up PIN like this:-
In the Contacts, click "Lookup", enter a <PIN#> and expects a return of result. If so, 100% cannot. Why? Lookup = NotesAPI call to Domino Directory. PIN number is a SQL record in the userconfig table and not part of the Domino data. If you are looking up a contact that is also a BlackBerry user in the BlackBerry Domain, then the BES messaging agent returns the Domino data from the NAMES.NSF and merge the PIN number value from the SQL configuration database.