Simply restoring the databases (make sure you restore both the Reporting Service and Reporting Server TempDB) on a different server will create the subscriptions on the new server, and you will be able to view these in the interface,
If, however, you mean you can't see them in Agent, this is to be expected. The Subscription details themselves are held in the RS databases, but the jobs are in the msdb.
Thom~
Excuse my typos and sometimes awful grammar. My fingers work faster than my brain does.
Larnu.uk