[Users] Authentication using auth_diameter

I am able to authenticate users using Radius without problem, but I am struggling to do the same using Diameter. I have installed the Diameter Server Client (DISC) that is mentioned in the auth_diameter readme, and have it listening on port 3000. When I start openSER there are no errors (i.e. the auth_diameter module loads), but the DISC client complains that the peer is unknown. Both SER and the DISC client are running on the same machine, so I added aaa://localhost as a peer, but that does not seem to help. Looking at a tcpdump output it shows that SER is trying to contact the DISC client from a range of ports but is never successful. Are there any further installation manuals, sample configurations or tutorials on this topic? Regards Dave