If you do it in stages, it should be ok.
Maybe cut a mitre a few mm oversize, making the first pass with the depth set at 20mm, then recut with full depth set.
Then move the track to the mark, and make a finish cut, still at full depth. That way you're only trimming the mitre cut, instead of trying to do it in one pass. Make sure you clamp the track, it will definitely try to wander with a cut like that. Make the cut slow, but steady - try not to stop & start.
