Please take a look at Bug 802756 and Bug 862306. Now we recommend SNAPSHOT transaction isolation level to run jBPM with MS SQL Server and regular QA process is getting ready for this on SOA-P 5.3.1. This recommendation and the script change (Bug 862306) should appear on official docs. Probably "7.5. Configure a Database for Production System Use" in Installation and Configuration Guide is the good place.