I’m using the Office 2010 RC and VS 2010 RC1.
There is an odd change in behaviour when trying to step into an Outlook 2010 Add-in from VS2010. Using VS2008, I set Outlook as the external program to start, set breakpoints and hit F5. The breakpoints were hit as expected. I upgraded the project to VS2010 but when trying to debug, Outlook started without hitting the breakpoints. I could see the Add-in loading and it was visible after Outlook started.
I was lucky enough to get a tip from a colleague that if I set the Start Action to Start project rather then Start external program, then it worked fine. We’re still trying to determine if this is an intended change in behaviour or a bug. I’d call it a bug, but this is my first attempt at writing an Office Add-in, so I’ve not been on any aliases etc to see if this was ever mentioned.
This may affect other Office applications, but I’ve not had a chance to investigate it further.
[UPDATE: Answers from Misha here: http://blogs.msdn.com/mshneer/archive/2010/03/19/com-shim-wizards-for-vs-2010.aspx]