ok, i managed to do it myself
thanks for the great tuts on this site!
i just deprotected the map with xdep, made my changes in the object editor and deleted the trigger... then i saved the map... after that i extracted the war3map.j of the protected map and added the file into the unprotected map
=> everything works fine
however, i got one more question...
lets say i got a trigger in gui and convert it to jass... how do i put this trigger now into a working mapscript, so it doesnt get fucked up? perhaps someone could explain that to me...
thx in advance