Well you'd have to make it so the heroes real death thing won't appear (So and so the level whatever so and so has fallen) then just say for event, unit dies, condition, unit is a hero = to true action show text message to all players saying blah blah blah... that simple. Unless you mean something else that i'm not cathcing onto
advanced --> game interface --> text - message - %s the %s (level %d) has fallen.,%s the %s (level %d) has been slain.,%s the %s (level %d) has been killed.,%s the %s (level %d) has fallen.
edit that if you want it to be at the left with the normal chat
if you want to trigger it do something like this:
event - a unit dies
conditions - triggering unit is a hero = true (boolean)
actions
floating text - create a floating text .........
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.