No you can select a different classifier ( e.g the default classifier or a custopm made)
but it can also be done via a firewall filter
but you also need to change the scheduler for the expedited forwarding class, as the default has 0% bandwidth reservation, low priority and 0byteof buffer, which means that any EF-packet which cannot be sent immediately will very likely be dropped ( in reality 0 % buffer means a minimum buffer of 2* MTU-size)
---> therefore I have attached the pic in my previous post 
regards
alexander