How should you go about a siege without quality infantry?

[Lord Winter]

I've also been having a problem with sieges, when the enemy does 'sally forth' they usually just sit in their walls and do not 'sally forth' at all!

This is enough to break the siege and gains them extra time (resets the time till surrender counter).

Any one know why, or how you get the enemy to actually 'sally forth' instead of dilly-dallying in the walls?

One way is to make the computer think they have a chance to win. You have to fight out numbered and win with tactical skill, not luck or pure strength .

Or you can wait for another enemy army to come and relive them then fight both armies in the feild.