preaching, stealth and sieging forts

[jeffr]

I searched, but couldn't find the answer to this one.

1. If I have a unit with stealth preaching in a province where I am besieging a fort, will that unit participate in the battle resulting from an army in a neighboring province attacking?

I know that if I have a unit with stealth preaching in a province that I own, that unit will participate in the defense of the province (unless that province contains a fort, in which case the preaching unit sits inside the fort).