Problems with Windows 2000 and WDS

I have a problem making an image of windows 2000 professional with WDS.
In my network we use WDS since RIS, and we image everything from XP to Windows 7 without problems.
Yesterday I needed to deploy a single old image with Windows 2000, and I discovered that it was stil uploaded in the old server RIS.
I correctly deployed the image, then I decided to move it over the new server (Windows 2003, WDS, Mixed Mode).
But when I sysprep my image with Windows 2000, I cannot upload it on the server. When I start windows PE (version 6.1, extracted from the Windows 7 DVD), in the combo box that is present in the first form of the upload software, I cannot see any disk.
This effect appears with every switch that I can use with Sysprep 1.1 available for Windows 2000.

Has anyone a answer for this question?

Greetings.