Oh i see, so the weapon id for life drain used as a weapon (like a vampire or a horror has) is the same as the id number for life drain used as a secondaryeffect? I'll give a try later on, thanks for the advice
Life draining weapons generally don't use the secondary lifedrain effect since dom2. They have a special damagetype (much in the same way as holy weapons) that is less powerful.
A weapon with the old life draining function is a lot more powerful, than the current lifedrains, but as long as you are aware of this it shouldn't pose any problems. Nothing wrong with a powerful weapon or two.