how to trigger rollback

Hi!

I have almost the same problem, except that my environment is a little bit different (SGWT Power 3.0, GWT 2.3.0, PostgreSQL 9.1).

I have a DMI class with two INSERTs, and if I throw a RuntimeException between those calls, the underyling transaction is nevertheless committed and the result od the first INSERT remains in the database.

I even tried to call this:
return new DSResponse("Some error", DSResponse.STATUS_FAILURE);

but the outcome is the same.

I wonder how can I programmatically trigger rollback in my DMI code?