[Kamailio-Users] I don't want "rpid" column but get an ERROR in "auth_db"

Hi, I don't want/need the "rpid" column in "subscriber" table but if I delete it I get an error:

------- Mar 18 14:49:47 [22377] ERROR:db_mysql:db_mysql_submit_query: driver error on query: Unknown column 'rpid' in 'field list' Mar 18 14:49:47 [22377] ERROR:core:db_do_query: error while submitting query Mar 18 14:49:47 [22377] ERROR:auth_db:get_ha1: failed to query database -------

After readin "auth" module documentation I've found a parameter:

------------ rpid_avp (string)

Full AVP specification for the AVP which stores the RPID value. It used to transport the RPID value from authentication backend modules (auth_db or auth_radius) or from script to the auth function append_rpid_hf and is_rpid_user_e164. If defined to NULL string, all RPID functions will fail at runtime. ------------

I expected that if I set: modparam("auth", "rpid_avp", "NULL")

then "auth_db" module wouldn't require "rpid" column, but I must be wrong since I get an error: ------ ERROR:auth:init_rpid_avp: malformed or non AVP NULL AVP definition ------

So, is there any way to avoid "rpid" column usage?

Thanks.