Reverse Serial loopback in ALTGX

Testing transceivers ALTGX for Arria II GX.

How to enable reverse serial loopback in ALTGX, Pre-CDR and After-CDR?

The problem is that megawizard ALTGX (Test basic or SHD mode) has this option but it doesn't generate any port input to enable or disable it, meanwhile serial loopback it does have this port input. Actually what's the point of that option in megawizard but it doesn't do anything?

Altera FAE mentioned that this is possible only with dynamic reconfiguration but I cannot find any information in the documentation.

thanks,

Diego