Unable to domain-join custom VHD on boot

I am working on the option to provision VMs that are domain joined on boot.

I have used this tutorial with great success: http://gallery.technet.microsoft.com/scriptcenter/Domain-Joining-Windows-fefe7039

I have no problem provisioning  servers with some of the build-in VHD's and they are domain joined on boot, but when i take a custom VM, sysprep it (according to this guide:http://thinkfirstcodelater.com/blog/?p=1424), Capture it and then uses it in my powershell script it just won't join the domain. I can do it manually once it has started but thats not the goal.

Does anyone have experince with this problem?

Please let me know if you need more information.

Best regards

Søren  Bjerre