Custom channel based on a sc_fifo

Hi all,
I'm a SystemC newbie and I'm trying to build a channel having the same properties as a sc_fifo channel with some parameters integrated like ID (integer value). I tried to define new interfaces derived from sc_fifo_in_if and sc_fifo_out_if implementing my new functions (getters and setters to my integer values) but I'm struggling to get them work since couple of days. The idea is very simple, but I have no clue how to get out with tris problem. Any help is welcome.