CAD files are not supported in services. Please see this resource for more information. If it's not listed there, it's not supported.
Many thanks Jonathan for the answer.
This imposes much more work to publish CAD files. We need then to convert them to feature classes and then to publish them.
It remains to say that this issue would be very challenging as the updates of CAD files are done in the AutoCAD and thus we need again to convert them to feature classes and so forth!
Best
Jamal
Just an idea for you....
If you convert the CAD files to feature classes and then publish them as feature services, you can edit the feature service directly using ArcGIS for AutoCAD. That way, the data is stored and available to everyone and the updates can continue to be made with AutoCAD without converting back and forth.
--Karen