I was putting together a demo environment earlier today and needed to publish a Terminal Services RemoteApp, so I installed Terminal Services (and IIS) on my Windows Server 2008 notebook. Later on, I noticed that Outlook was not working in cached mode. I found that offline store (.OST) files and features that rely on them are disabled when running on a Terminal Services server.
This is a known limitation: Terminal Services and Outlook Cached Exchange Mode do not work together, as cached mode consumes too many server resources in a multi-user environment.