[spacht]

To make it clear, stealthy troops on attack order will only fight during the magic battles phase (turn resolution nr. 6) if you combine them with magically transported troops or remote summonings targeted on the same province. By itself, stealthy troops on attack order will attack in the movement battles phase (turn resolution nr. 14).

As i learned in my last mp game this combination is really the only useful way to utilize stealthy troops.