Also, an alternative for me is to publish my CAD files as a mapservice with ArcGIS 9.3, to cache it and then to use the cache with a 10.1 mapservice.
The problem I have in this scenario is the one I described in the previous post : Adding DWG Layer using arcpy.AddLayer doesn't preserves CAD symbology as it does when you add the layer manually in ArcMap.
Adding my thousands of CAD files at once manually craches ArcMap.
Does anyone know how to add DWG layers to ArcMap using python and how to preserve the CAD symbology ?