[Serusers] how to make use of the function, is_from_local, in ser?

Dear all, We want to use multiple mediaproxy by using dispatcher. We set SIP_DOMIAN = mydomain.com, set up two user: A(a)mydomain.com & B(a)mydomain.com. They both register successfully. When user A & B dials for each other, the functions of is_from_local and is_destination_local both return False, so the dispatcher only return "warning: no proxy available for call: mydomain.com -> *.*.*.*" In mysql, the domain table is empty, too. How come? Thanks in advance. My ser config is as follow: debug=9 fork=no log_stderror=yes check_via=no dns=no rev_dns=no listen=218.97.252.38 listen=127.0.0.1 alias=sensates.com alias=218.97.252.38 port=5060 children=4 fifo="/tmp/ser_fifo" loadmodule "/usr/local/lib/ser/modules/mysql.so" loadmodule "/usr/local/lib/ser/modules/sl.so" loadmodule "/usr/local/lib/ser/modules/tm.so" loadmodule "/usr/local/lib/ser/modules/rr.so" loadmodule "/usr/local/lib/ser/modules/maxfwd.so" loadmodule "/usr/local/lib/ser/modules/usrloc.so" loadmodule "/usr/local/lib/ser/modules/registrar.so" loadmodule "/usr/local/lib/ser/modules/auth.so" loadmodule "/usr/local/lib/ser/modules/auth_db.so" loadmodule "/usr/local/lib/ser/modules/uri.so" loadmodule "/usr/local/lib/ser/modules/domain.so" loadmodule "/usr/local/lib/ser/modules/textops.so" loadmodule "/usr/local/lib/ser/modules/nathelper.so" loadmodule "/usr/local/lib/ser/modules/mediaproxy.so" modparam("usrloc", "db_mode", 1) modparam("registrar", "use_domain", 1) modparam("auth_db", "calculate_ha1", 2) modparam("auth_db|domain|uri_db|usrloc","db_url","mysql://ser:heslo@localhost/ser") modparam("domain", "db_mode", 1) modparam("auth_db", "password_column", "password") modparam("rr", "enable_full_lr", 1) modparam("registrar", "nat_flag", 6) modparam("mediaproxy", "natping_interval", 5) modparam("mediaproxy", "mediaproxy_socket", "/var/run/proxydispatcher.sock") modparam("mediaproxy","sip_asymmetrics","/usr/local/etc/ser/sip-asymmetric-clients") modparam("mediaproxy","rtp_asymmetrics","/usr/local/etc/ser/rtp-asymmetric-clients") ............................. Best regards,