Hey Wouter,
Sounds like you are in same boat I was in after upgrading to X3e Producer (assuming these same conditions-
1. Previously owned/installed AD1 which was working before upgrade,
2. AD2 would only play 4 kit pieces from a demo version of Fairfax Vol 1 preset included in the upgrade,
3. All other presets were demo only).
I played with the AD2 installer for awhile, verifying my XLN acct, etc. I finally emailed the XLN people about the problem to which they replied that for some reason they needed to manually change a setting in my account for the before-mentioned kit packs from AD1 to be enabled in AD2. One or two others on the forum have stated they have had same problem with XLN needing to give personal attention to the situation also. Hope this helps.
Best, HeyDan