This setup is as easy as it gets, just about plug and play.  If you power down the security system, then power back up with Automation module plugged in, it learns in the automation module and starts talking to Crestron.  If your Crestron module is proven and has worked before, and the programming is as it should be, then you have one of two possible issues: bad cable (straight through is used), or the automation module itself is bad.  I have seen bad automation modules, so don't doubt that part too much. There are occasions in which a reboot of Security system AND a reboot of Crestron is what got things going.
Again, this is considering the Crestron module has been proven to work before and programming within Simpl is properly connected.