Editing Max Life (help)

I asked this a while ago, but no one would help me, so i'm asking it agian. How do you use triggers to edit a unit's max HP?

The event would be somthing like "player says life up". Then the trigger would add (for example) 300 HP to the selected unit's maximum life.

The Bonusmod trigger in the Repository would solve my problem, but since I know NO jass, I can't use it (plus, the creator never responded to my PMs). If someone could help me out with this I be most grateful...

I think there aren't any triggers giving max life, but you could try to add an item ability with permanent +max life with triggers.

I believe you should look into WEUnlimited Advanced Upgrade triggers.