Problem with custom Scorestreaks

[BeepBeeep]

Herro there!

So, i want to give players an increased melee range when they reach a 5 killstreak.

Im using this:

do5Streak()
{
	      setDvar( "player_meleeRange", 900); //Or maybe self setClientDvar ? We tried that, but same results.
			  
              Killstreak5 = spawnstruct();      
	      Killstreak5.titleText = "5 KILL STREAK!";
              Killstreak5.notifyText = "^1You are now a long range ninja!";
	      Killstreak5.sound = "mp_capture_flag";
	      Killstreak5.glowColor = (0.3, 0.8, 0.3);

              self thread maps\mp\gametypes\_hud_message::notifyMessage( Killstreak5 );			  
}

But when testing it only works for me(so it's a host only dvar?), not for my friend.
Means, he gets the "5 Kill Steak" message, but not the "extended" melee.

Is there any other way to do it or is this not possible to do?

Any help is appreciated!