Here's a link to a site which has scanned the Citroen parts microfiches for the XM both Series 1 and Series 2.
The file sizes are large and would take a very long time to download via a 56k modem although not impossible. Download software is to be recommended for this purpose so that you can download a bit of the file at different times. Otherwise a straignt download from windows could crash at the last minute and you'd lose everything.
http://rammstein.dfmk.hu/~xminfo/
cheers
noz