How To Stop Creature's Hp Regeneration?

For example, i need to script boss that has 60% of hp at start.

I’ve tried to set it to 0.6*maxHP in Reset, EnterCombat etc but that dont fit as boss regenerates his hp while not in combat anyway.

There is some boolean m_regenHealth in Creature class but its protected.

Any suggestions?

creature_template.RegenHealth

Thank you!