Whenever ProcessRequest returns an error code, the engine considers this a failure, although the transaction may not roll back immediately, depending on the error handling, if any, implemented in the procedure. The provider is responsible for cleaning up data and rolling back changes for the failed call because the engine will not call RollbackRequest for the failed procedure. (However, it will call RollbackRequest for all the successfully-executed procedure calls.)

HRESULT ProcessRequest  (
	IXMLDOMNode *pXML
);

No sample code.