The Billing Platform (lite) connector currently does not see all of the BP tables. This enhancement would bring in all tables including custom ones and custom fields.  You can get a listing of tables from the Entities object and the fields are found in Entity Fields. 

Additionally we would like to see this connector be incrementally refreshed instead of a full refresh.  Our Billing Platform system will contain millions of records and doing a full sync daily will be very costly and very poor performance.