firast up, that's the way it works with eggdrops, it's nothing to do with mIRC itself.

secondly this is what i used for dcc chats

Code:
 on 1:INPUT:=:{
  if ($left($1,1) != /) {
    haltdef
    msg $active $1-
  }
}


then in my /msg alias i have this line

if ($chr(61) isin $1) { echo -ai25 $+ $calc($len($1) + 8) 13<15 $+ $me $+ 13> $2- | .msg $1- }