If you are you may want to update your VSTOR. As I understand it has been updated with support for Office 2003 and 2007 under Vista but there isn't much detail on what was added and fixed "This version is a July 2007 update that contains enhancements and bug fixes to the original VSTO 2005 SE runtime; for example, it contains fixes related to add-in support for Microsoft Office Outlook." is all the doc that comes with it.
Note that there are two different updates, one for design time (adds support for VS 2008!) and the VSTOR itself.
Design time update
Also updated are the instructions for deployment of VSTO Solutions on MSDN:
While you are in VSTO mode you may also want to watch this video of Steve Fox and Paul Stubbs on OBA and VSTO they made at Tech-Ed 2007.