im sorry about this, but seems to be another stupid question from a newbee

i want to controll the hold attribute from a multiball. i made a script in a switchobject: setattribute(MultiBall,'hold',x);
but it doesnt run?
when i want controll the grid all is running well. isnt hold an attribute? or cant i controll it?
i also test it with 3 balls in the mutliball and try this script: setattribute(MultiBall,'hold[0],x);
only to controll the hold attribute of the first ball. doesnt run
