I did some tests yesterday and today, but unfortunately, which ever system files I try (samsung or special S3 mini), I can't get a RSAP connection. Instead I'm always connected via HFP.
I don't know the specific model number of the car phone, but I'm certain that it's one of these VW Premium (5N0 035 730D, 3C8 035 730A, 3C8 035 730B, 3C8 035 730C) build into a Skoda Octavia BJ2013.
I'll send you some logs that I grabbed with the rSAP Trail App, shortly via mail. Maybe that helps to debug.