Received an email today from the Thai office in Brussels filling in some details:
Bangkok-Brussels, TG934
Tuesday, Thursday, and Saturday
00.30 - 07.00 with Boeing 777-200ER
Brussels-Bangkok, TG935
Tuesday, Thursday, and Saturday
13.30 - 06.20 +1 with Boeing 777-200ER
Tickets can be booked as of 1 July 2011 onwards.