English to Swedish Law/Patents Law: Contract(s) Villkor för patentregistreringsfirma

Under rubriken Avgifter:

"You acknowledge that it is our policy not to pay accumulated annuities or back fees arising in certain countries at the time of grant or acceptance of an application, and it is your responsibility to arrange payment of such fees directly with your associate."

Jag hittar ingen bra definition av 'back fees'.