Adjusting a unit's life with triggers

I'm having problems with a summoning-like ability, where the summoned unit have a varying amount of maximum health.
I have tried using the item health boost ability, but that does not work.
I have also tried to use the SetUnitState(u, UNIT_STATE_MAX, #) thing, none of them works.

Any suggestions? What can I do?

SetUnitMaxStateSystem by Blade.dk

check spell sessions there is great spell using max state mod.
session 5 or 6

Thanks, that's exactly what I needed!