Hi, Cecile.
Could you please update me on the current status of the issue? Are you still observing Gluu's behaviour that doesn't conform to the standards? Have you already tried to update it to the latest (ver. 2.3) CE release (and if you have then whether or not this helped to resolve the issue)? If you haven't, I would have recommended to try it before anything else, but if you are pinned to the 2.2 release by some insurmountable circumstances, we can continue to work on the issue together.
I also would like to know which OS do you use as Gluu's host server (it's exact version/distro/family).
Regards,
Alex.