Clickonce update requires new prerequisite

Hi,

I have a Clickonce application currently deployed with .NET 2.0 as a
prerequisite. This application has been updated to use features in .NET 3.5,
(file association). When my current app sees the available update the install
fails because the .NET 3.5 framework is not present. Initial installations
are fine.

How do I enforce installing of a prerequisite upon update of a Clickonce
application?
--
Kenneth Lemieux
Project Engineer
Whelen Engineering Co., Inc.