hello,
in the Arccatalog-Metadataeditor all http links have to be given in lower characters. Upercase like .../GIS/test/AT/... does not work - this is my experience. For SDE and Metadata try to make an WAF (Web Accesible Folder) on server side. Enabel the folder for Browsing. In Geoportal use the option Register resource on the network with option WAF. All xml files (copied from sde with batch processing once a day) in the folder will synchronized well.
werner