The basic problem is that GSS 2.5.1.2266 is not validated with WinPE versions other than V2, so it's really in your hands to find workarounds. I would recommend reading this article by Terry Bu:
https://www-secure.symantec.com/connect/articles/creating-and-using-winpe31-image-gss-251
as he has done some sterling work on finding ways to get GSS working on newer versions of WinPE.
Aside from that, there are other ways of arranging a domain join if you cannot get it working through the ghost system, using the Microsoft methodologies.