Asterisk and REFER authentication


The service I am using requires authentication.

In sip.conf, setting:

Gets the authentication working for the INVITES but when I try a transfer, I can see the REFER but then asterisk quickly says BYE. The provider sends back a 401 UNAUTHORIZED but asterisk never resends the REFER with the required authentication info.

Is there a way that I can get Asterisk to authenticate on REFERs?