[SR-Users] modify FROM field in the "failure_route" block

Hi, When I am trying to modify FROM field in the "failure_route" block I get an error message: failure_route[1] { ... uac_replace_from("$avp(i:204)"); append_branch(); t_relay(); } Not starting openser: invalid configuration file! Mar 22 10:51:39 [6457] CRITICAL:core:yyerror: parse error in config file, line 662, column 32-33: Command cannot be used in the block Mar 22 10:51:39 [6457] ERROR:core:main: bad config file (1 errors) It seems "uac_replace_from()" can not be used in the "failure_route" block. What's the correct way to modify (appending a tag) FROM field in the "failure_route" block? Thanks, R