Всем добрый вечер. 
Как в pjsip_wizzard установить поле: Authorization: Digest username= ?
 Победил. Решение (pjsip_wizard.conf):
...
client_uri_pattern=sip:UUUUUUUUUUU@${REMOTE_HOST}
outbound_auth/username=uuuuuu
...
где UUUUUUUUUUU - username, uuuuuu - auth username
> pjsip show auth UUUUUUUUUU-oauth 
  I/OAuth:  
======================================================================
     Auth:  UUUUUUUUUUU-oauth/uuuuuu
 ParameterName  : ParameterValue
 ===============================
 @pjsip_wizard  : UUUUUUUUUUU
 auth_type      : userpass
 md5_cred       : 
 nonce_lifetime : 32
 oauth_clientid : 
 oauth_secret   : 
 password       : ************
 realm          : 
 refresh_token  : 
 username       : uuuuuu