Visual Studio Tools for Office
A couple of quick notes for anyone else reading this post that reflect a bit of what MathMax and I worked through off-line. The most important thing to recognize is that deployment has changed for the better in VSTO 3 / Office 12. Customizations are now written to the Click-Once cache, so there is no longer any need to muck around with CAS settings. Deploying a VSTO customization is now a simple process:
1) Use the deployment wizard to generate the necessary deployment files and push them to the install location.
2) Ensure that the prerequisites exist on the target machine; .Net FX 3.5, VSTO 3.0 Runtime, and Office applications and PIAS.
3) Run the generated setup.exe (or double-click on the deployment manifest) on the target machine--this will install the customization to the local Click-Once cache.
4) Copy the document to the desired location and open (your customization should run). If you wish to run the document from a network share, the share must be added to trusted locations in the Office Trust Center.
Complete documentation for VSTO 3.0 (Beta 2) deployment can be found here: http://msdn2.microsoft.com/en-us/library/bb386179(VS.90).aspx
Note that Office 11 projects are still stuck with the VSTO 2.0 deployment model.