Better late than never... I've been away from music for a while (indulging in my fishkeeping hobby) but just for the sake of completion and for the record:
The original 1036 module from the ARP 2500 did do Track & Hold, and there was nothing wrong with my Behringer module.

Problem was that the Trig switch position requires a hefty trigger voltage before it reacts, so I tried with the Gate position, and that indeed sets it to Track & Hold, and correctly so.