Help! - Property Pages in an Add-in

I'm currently using Visual Studio 2008, with Microsoft .Net Framework 3.5.

I'm looking for assistance in writing a new visual studio add-in that adds an additional property to my references, the documentation and books I've used so far, aren't very clear on how to do this.

I'm familiar with creating add-ins that are ran from the tool menu, or a right click context menu; but I have no clue where to start to write an add-in that adds a property to a property page.

We're using visual studio across different machines, different environments, and all our shared libraries are in one shared network store. What I'm trying to do, is add a "Static" property, to the References property page that accepts a true/false; and if set to true, switches the hint path inside the csproj file from using the "../../../" format to using "c:\sharedlibraries\mydll.dll"; when flipped back to false, changes it to use visual studio's default hintpath again.

One, if this is already being done by another add-in, or can be enabled in Visual Studio, someone please enlighten me, cause I missed it :).

Two, if it's not, any of the add-in geniuses out there that could shed some light on where to start, or provide a helping hand would be greatly appreciated.

Thanks
Brian

Any Ideas? Spent a decent amount of time this weekend trying to find a way to get at those property pages and struck nothing. I'm lost.