Midiclock drifting..?

[dekenno]

Pls help. I?m hopefully just doing something wrong, right?
Thing is, im trying to record tracks in Cubase SX and midi is so strange. I have set the TI midiclock to follow external sync, told SX to send clock to TI and no matter what i do it wont play in sync. I can get the TI to play synced every now and then but only for a short period of time. And if i go back to the start of the song it will be out of sync again. Toggling between the choices in MIDIclock menu makes it go back in sync but only very briefly. Please give me a hint. I must be doning something wrong here right?

It?s a v1.0.8 TI and i?ve tested it on both SX 1,06 and SX 3..

thanks in advance