Daniel,
I built my config on the principles of the one you sent me privately and it works! Thank you very, very much.
It seems that I had to start using force_rtp_proxy() to get it to work, though. I cannot produce the same result with rtpproxy_offer() / answer(), even with the exact same flags. I think it is because they are broken. I started using them because the 1.5.x documentation insists that force_rtp_proxy() is deprecated and provided for "compatibility" purposes, yet it seems that it is necessary to use it in order to make rtpproxy work.
What do you think?
-- Alex