You shouldn't need to, they are usually arranged for you on available dates. Everything else will be unavailable due to domestic schedule and it would be really irritating trying to set up your own.
As Nomis said in the 07-08 season you cant arrange any friendlies as it would be too short notice and the domestic season cannot be interrupted. Click next season and there should be some available dates for friendlies, thats what i think what your saying.