Thanks to Ian, and to Rainier and Olivier from the Startomaster and MGL side, I now have PAW traffic on my MGL iEFIS. Here's one at FL140
Basically, the TX pin from a free USB port should be connected to a free serial port on a RS232 connector on either the iBOX or directly to the iEFIS light. I used a usb-RS232 serial adaptor from mouser, and set the USB port from the PAW configuration page to DYNON TRAFFIC and 19200 baud rate. In the MGL unit hen activate the Traffic option on the free serial port that you chose, and configure it as "Flarm". Pretty straightforward.
I hope this is useful for other MGL users.
Best regards, and CAVOK skies.
Carlos