Its not the answer yet, but one 1/2 way hack is to use:
[assembly: AssemblyDescription("One Line of Content Here")]
And that shows up under "Comments".
(still researching, this is something I've wanted for a while.)
I believe those properties are stored in a "named stream" a.k.a. "seconary stream". That is, it's a data store that sits parallel to the actual file contents within an NTFS drive.
I have wanted to do exactly as you say for a long time, but MSDN has poor-to-no documentation on the named streams, and it looks like some kind of voo-doo magic that only the people on the Microsoft Office team know how to manipulate. A couple of months ago I was able to get a command-line stream to read and write to that data, but it was a fragile thing that used some secondary behavior of an obscure command (I don't remmeber exactly), and it was not at all applicable in the general case.
It is very frustrating.
Your compiler does not support it. AssemblyFileVersionAttribute and all work because the compiler generates a win32 resource in your assembly called VERSIONINFO with that information in it. That is what windows is reading. Other attributes are just saved as metadata along with your code.
You could make a tool to change the VERSIONINFO resource after you compile.
The only tool that can control any field of VERSIONINFO structure from the command line and hence is able to add an additional property during a build process is Resource Tuner Console:
http://www.reseditor.com/rtc-solution-version-info.htm
The $199 price seems a bit high... but if you don't want to spend days mucking around with C/C++ then it's a steal.