'Custom audit' can be as simple as logging information you want to keep for as long as you want to keep it. Start by figuring out what you want to audit and how long, then create a database to store the information, then create jobs to record that information.
Gail Shaw
Microsoft Certified Master: SQL Server, MVP, M.Sc (Comp Sci)
SQL In The Wild: Discussions on DB performance with occasional diversions into recoverability