I'm new on this forum

I use FC from several time
I've recently installed XE and updated to 570 public preview on a Workstation with Win XP SP.3
I've discovererd an issue with XE
I'm not able to see thumbnails for AutoCAD DWG files
In this image, you can see the same folder, shown on right with detailed informations and on left with Thumbnails view

As you can see on the attached image, PDF files (but also JPG, TIFF and all the other extensions) are correctly shown as preview.
DWG files are NOT shown.
In the previous version of FC, it works properly. If I use Windows File Manager, I can see the thumbnails.
AutoCAD version is quite recent (2009) so I'm sure that the preview is supported
Do you have some suggestions? Thumbnails function is very important on my job
Thank you for your help and apologize me for my poor english

MBT