How to migrate existing data from jBPM 5 database tables to jBPM 6 tables ?

Issue

• While porting the jBPM 5 based data from Red Hat JBoss BRMS 5.3.x database tables to Red Hat JBoss BPMS 6.0 database (used by jBPM 6 engine) will there be any impact on the application in any way in scenarios, like the application relies on the BRMS database tables (e.g. VariableInstanceLog) to identify the process instance id tied to the application id ?
• During the migration from jBPM 5 to jBPM 6 (as part of application migration to Red Hat JBoss BPMS 6.0), users normally want to migrate existing data from jBPM 5 database tables to new jBPM 6 tables. The expectation is after migration process is completed all Process instances and Tasks created in jBPM 5 should work in jBPM 6 as well. Is there any tool or technique available to map the tables from jBPM 5 to jBPM 6 ?