Hi to all,
It seems I fix the problem, setup config file in this way and he write in msg_body column the SDP part of the message
loadmodule "/usr/lib/openser/modules/acc.so"
modparam("acc", "db_url", "mysql://openser:openserrw@localhost/openser") modparam("acc", "db_table_acc", "msg_body") modparam("acc","db_extra", "msg_body=$rb")
if (method=="INVITE") acc_db_request("Prova", "acc");
thanks davide