Encrypt app.config file in class library

Hi,

I have a solution containing 2 projects - a class library project and an Asp.Net Web Application project.  Within my class library project, I have set up some Application settings (by right clicking the project, choosing 'properties' and then settings).  This has automatically created an app.config file for me within the class library project.  What I would like to know is how would I go about encrypting these keys in my class library project from a test page I have set up (Encryptconfig.aspx) which is in the web application project.

I have successfully encrypted the connection strings in my web.config file which is part of my web application project, but am not too sure how I'd go about encrypting my app.config file in the other project.  The page Encryptconfig.aspx looks like the following:
 
using System;
using System.Data;
< ...