Using TDP 3.8 BASE Edition, I finally got this reply from DELL support:
>I am sorry, but you are licensed only for Base edition. Cross-connection is now only >supported in the Pro Edition.
>
>We used to support Cross-connection in base but we used the Access jet engine to do >the execution. That engine was very limited and since it is owned by Microsoft we could >not enhance it. So we wrote our own cross-connection engine where the non-standard >names are supported.
>To get support for this issue you will need to use the Beta or upgrade to Pro. I can send >you a trial key for Pro Edition and it will work in your current version of Toad Data Point. Let >me know if you want to send it.
So I am wondering, why this general fact is not published in the Forum. I had to do serveral testings, to generate Toad Support Bundles and to write some E-Mails to get this!