Hi there.
The WWW-Authenticate header is included to UAS 401 challenge response upon REGISTER from UAC. This response does not generate any GlobalCall event; instead, GlobalCall compares this header against authorization data the app provides via gc_SetAuthenticationInfo( ) before calling gc_ReqService() and sends digest of authentication info in Authorization header of the second REGISTER; the app has no control of it. The GCEV_SERVICERESP is generated when REGISTAR subscription is terminated, whether with success or failure. If the final response from UAS contains WWW-Authenticate, you can retrieve it as described in 4,.9.2 and 4.9.4 at the location you specified above. However, I don't see how you can use this info: according to RFC2617, this header is a property of UAS, and UAC includes Authorization header as a response to 401/407. In other words, the app cannot set or retrieve WWW-Authenticate header in most cases, and it does not need to do that. All the app needs to take care of is to provide right quadruplets before gc_ReqService() is called, and if match between the quadruplets and WWW-Authenticate content is found, the second REGISTER with Authorze header is sent automatically by GlobalCall