[OpenSER-Users] append_hf() and failure_route issue

Hello all, I'm having some trouble with failure routes and custom SIP headers. In FAILURE_ROUTE I set the ruri to a new destination. This destination needs a custom SIP header. When I add a SIP header with append_hf() (from within the failure_route), this header is correctly sent to the first IP of the destination on t_relay(). However, when this destination fails with 503 or timeout, the built-in DNS based failover doesn't add the custom SIP header to the new requests for subsequent IP's. When the SIP header is added from REQUEST_ROUTE the header is sent to all destinations by the DNS based failover mechanism. How do I get the DNS based failover to send my SIP headers all the time? (The same problem is present with uac_auth()) -- Greetings, Alex Hermann