Control Users Gateway Gtalk

Is there a way to keep track of contacts from
Gtalk gateway for users of Openfire in Spark?

There is no way to track this information because it is not stored locally. It is stored in temp roster cache when the users first logs in, but they do clear over time. Only S2S contacts and local contacts are stored in the roster. Being that Gtalk is xmpp have you tried doing a S2S connection to those buddies? The format for the accounts would be username@gmail.com.