[Users] acc module and logging incomplete calls

My SER distributes calls to a bunch of Asterisk servers. Here's my route: route{ setflag(1); if (!mf_process_maxfwd_header("10")) { log("LOG: Too many hops\n"); sl_send_reply("483","Too Many Hops"); return; }; if (loose_route()) { t_relay(); return; }; if(uri==myself) { if(method=="REGISTER") { save("location"); return; }; }; if(method=="INVITE") { record_route(); if (uri=~"^sip:1[0-9]*{10}@192.168.1.10") { ds_select_dst("2", "0"); forward(uri:host, uri:port); return; }; }; } I am trying to log all calls including failed, busy, congestion, incomplete using acc. Strangely, in my acc table I only see records affiliated with BYE and not with INVITE. Thru, all I see are successful calls. Is there a way I can make acc log incomplete calls?