PHP + Jabber bundle with AUTH MECHANISM: Kerberos/GSSAPI?

Question

PHP

Good day!
Works inside a Windows-domain Jabber server OpenFire. It has Kerberos/GSSAPI domain authorization configured. There is a task - to write a PHP script that could simply send notification messages to users from the same domain user.
Having dug into the search, I found classes with algorithms for authorization by the DIGEST-MD5 and PLAIN mechanisms, but with Kerberos / GSSAPI something is nowhere to be found and how to use it is not clear.
Tell me, can anyone come across such a task-problem?