[Serusers] Appending different authorization tokens for every branch.

Hi, I need SER to sequentially try 3 URIs, while using a unique token for the 1st and 3rd UAS and no token for the 2nd one. I have tried using 'append_hf' and 'remove_hf' functions to add and remove header fields, but it does not exactly do what I need. Calls to "remove_hf" do not make any difference. I guess 'remove_hf' only removes header values from the received INVITE message. I have tried using the CPL logic below. Any help would be very appreciated. Best Regards, Dmitry route { .. append_hf("P-OSP-Auth-Token: open.settlement.token.number.1\r\n"); t_on_failure("1"); t_relay(); # Want the 1st UAS to receive only the token above - WORKS! .. } failure_route[1] { .. remove_hf("P-OSP-Auth-Token"); t_on_failure("2"); t_relay(); # Want the 2nd UAS to not receive any tokens - does NOT work, it receives the token from the 1st attempt .. } failure_route[2] { .. append_hf("P-OSP-Auth-Token: open.settlement.token.number.3\r\n"); t_on_failure("2"); t_relay(); # Want the 3rd UAS to receive only the token above - does NOT work, it receives both tokens from the 1st and 3rd attempts .. }