If you haven't downloaded it yet, you must download the Microsoft IntelliSense XML Files for Microsoft Visual Studio Tools for the Microsoft Office System Solution Developers. This download is a must have for any Visual Studio Tools for Office 2003 or 2005 installation.

This download provides summary descriptions of types, members, and parameters to IntelliSense ToolTips in code and in the Object Browser for the native PIAs for Word, Excel, Outlook, and MSO (Office Shared Features). The download works in both VSTO 2003 and VSTO 2005, and the download complements the IntelliSense ToolTips for the VSTO classes that already ship as part of VSTO 2005.

This takes your your intellisense from this "what does separator do":

to this "oh, so that's what separator does!"

You can find the download at http://www.microsoft.com/downloads/details.aspx?FamilyID=e455f3d6-4177-4876-bcb3-2791625ea7ab&displaylang=en.