The liquibase exension system allows you to easily plug new functionality into Liquibase to support new database types.
You can see some examples at:
At a high level, you need to implement a new liquibase.database.Database class and then new implementations for sqlgenerator, snapshot, and datatype classes that are causing problems. There is some documentation at liquibase.org/extensions but more needs to be written and will be soon.
Let me know what you have for questions and problems.
Nathan