I finally got tired of changing this manually, and set out to find the way to do it once and for all. My google’ing turned up this article as a primary starting point. I found the explanations a bit convoluted, so here is in brief what needed to be done with RegEdit.
In the following key (or keys on a 64 bit machine):
you must change the RegisteredOrganization attribute, and voila, all your future assemblies are belong to us.
I have no explanation why this doesn’t get set up “correctly” during installation.
If you need to change this information in the source base after the fact, then search/replace your AssemblyInfo.cs files for [assembly: AssemblyCompany("Microsoft")] and [assembly: AssemblyCopyright("Copyright © Microsoft 2009")] and setup projects .vdproj files "Manufacturer" = "8:Microsoft." (remember to check out of source control first!)