Make includeObjects and excludeObjects affect which objects are snapshotted

I try to do diff using includeObjects between JPA entities and database (using liquibase-hibernate) as well between IBM i DB2 and PostgreSQL databases. The problem is that it fails due to various reasons. The irritating part is that it fails on entities/tables that I'm not interested in getting a diff for (either because they have already been migrated or because the shouldn't be migrated at all), but since a full snapshot is made before includeObjects and excludeObjects are considered I can never get it to work.

Another problem is that the DB2 database has a very big amount of tables, so a full snapshot would take a lot of time to get if it had worked.