Brewing a rebellion

Is there a certain trick to causing rebellions? This morning I was tooling around with the English in Late; trying to get Sir Roger Mortimer to lead a rebellion against Edward II, sort of like in real life. I sent the King to Ireland (cutting of the route back, of course), gave Mortimer a huge army in Wessex, and made certain that only the most disloyal generals were in charge armies in the rest of my provinces. I waited and waited to no avail. Eventually I decided that maybe a good loss might prompt the kingdom to rebel. I gathered the most loyal troops and sent them all against the Scottish rebels and fought the battle in the most incompetent way imaginable. I lost nearly my whole force and still I yielded nothing. Then I thought that maybe losing a province would start the revolution. I sent the armies in my only French holding, Aquitaine, against the French. Needless to say I was mercilessly pummeled, but still nobody rebelled. What gives? Why is it so hard to get people to rebel against my lackluster gay monarch?

Send a crusade against the most powerful non-Catholic faction. If its defeated your monarch will lose intrerest. Also try to assasinate your generals with crappy assasins. They'll fail but if they find out who ordered it your generals will lose loyalty.

Excessive taxation probably helps. Getting the royal line killed off gives a 50/50 chance of starting a civil war upon the monarch's death.

Have your king lose battles and ransom him back if you want to(captured). Attack and retreat against the Scotts(hesitant)... never use him to actually fight, just let him withdraw at the begining of the fight(coward?). Figure out a way to get bad steward, that'll definately make everyone hate him.