Outlook 2007 VSTO Add-in deployed by click-once doesn't detect published updates

I have created an outlook 2007 add-in project in vs2008, targeting .net 3.5, then migrated the project to vs2010.

I have then published the project from vs2010 to a web site, and installed the add-in using click-once to a virtual machine running xp, .net 3.5 sp1, and outlook 2007. This all works great and I can see my add-in within outlook. Publish update settings are set to update the add-in at startup rather than every 7 days.

However when I then make a simple change to the add-in, update the AssemblyVersion and AssemblyFileVersion of the add-in project, and then publish the upda开发者_StackOverflow中文版tes, when I run outlook it doesn't detect that there is a new version, and just runs the current one that is installed.

I can see that the publish has generated a new setup.exe and added a new folder to the 'Application Files' folder with the current (autogenerated) publish version.

Can anyone suggest how I can get the update to be deployed to the client?

Edit:

I left the VM without outlook running for a while (over lunch) and then came to start it up and it detected the latest update and installed it. However now when I make another change and re-publish it is not picking it up. I wonder if this has something to do with caching of the files. I have deleted all the temporary internet files on the client vm, but that didn't help.

The reason it is not detecting published updates was due to iis caching the pages.

I added the expiration common header in IIS7 manager and set it to expire immediately, and after that the addin detected each change as it was published.

Double-check and make SURE you have it set to check every time they open the application and not just once a day.