LG69T(AP) enabling IMU

When trying to enable sensor reading, using:
$PQTMSETNMEAMSGMASK,0x800000007C
$PQTMSETNMEAMSGMASKOK
14

there is no visibile change in the NMEA output.

What is the proper way of enabling IMU sensor readings?

[SOLUTION]
Simply write:
$PQTMSETNMEAMSGMASK,0x80000000*7C

The documentation is poorly written and the second message is actually received from the board.