Business Rule Engine for OutSystems - Suggestions?

We are currently exploring use of Business Rule Engine with Outsystems but would like to know if anyone used any open source library (ex: Drools.NET) integrated to platform or could suggest one.

Thank you in advance.

OutSystems Version: 8.0
I too have a need for this type of functionality.  My potential client has a very complicated business process and while I could do this directly in Outsystems (probably) I get the feeling that using a rule engine would be a better way to go once the extension is built.
Have you looked at BPT that is built into OutSystems? It may not be available in the Community Edition or Personal Edition, but it may very well fit your needs.

From what I understand BPT only covers Business Process Management (BPM) and does carry a Business Rule Engine.
Rodrigo -

I've found that different companies define these things a bit differently... you should check it out if possible and see if it meets your needs. It's built into the system and supported by OutSystems, so that makes it a very attractive option.