[SR-Users] topoh problem with bye from trunk

Hi all. I use topoh module for topology hiding and this is my config for topoh: modparam("topoh", "mask_key", "my key") modparam("topoh", "mask_callid", 1) modparam("topoh", "callid_prefix", "!!:") modparam("topoh", "sanity_checks", 1) modparam("topoh", "mask_ip", "x.x.x.x") modparam("topoh", "uri_prefix_checks", 1) modparam("topoh", "uparam_name", "line") modparam("topoh", "uparam_prefix", "sr-") modparam("topoh", "vparam_name", "branch") modparam("topoh", "vparam_prefix", "z9hG4bKsr-") and also i use: modparam("dialog", "lreq_callee_headers", "TH: dlh\r\n") for dialog module. my calls come from asterisk and routed to the carrier(sip trunk) and vice versa, when i make a call from asterisk every thing works fine until the call hanged up from the carrier. at that modemt the kamailio send an 481 call/leg transaction does not exist. if call dropped bye the asterisk user everything works fine. how can i solve this?