Then periodicly check if units have that aura-buff, if they have, make them invulnerable. if not, make them vunlerable again.
Gotta go bed, and dont have editor open. Altough it should work I think. Maybe the hard thing is to track them and such in an easy way without checking every single unit on the map?
13est's solution is the best
Because first off, when a dummy casts the ability, it will make the hero invulnerable and unless that's what you want to do, BBV doesn't work like that.
Ghan has said he has fixed this. Monovertex please confirm this fix. This was only a problem with people that had signatures in the upper levels like not the special members but the respected members.