Intranet zone and code access security

I am currently investigating code access security to see how it could be
useful in our product. As part of my work it is necessary for me to
demonstrate how code access security works over the intranet zone. My
question is how can I set up a test over this intranet zone?

This is my senario:-

I have an asp.net web application that contains a button. When the button
is pressed a dll is called. The dll contains the declarative syntax line

[FileIOPermissionAttribute (SecurityAction.Demand Write = "e:\\")]

Therefore the calling code (the web site) must have permission to write to
the harddrive to be allowed to access the function. The function, if
called, writes to a file on e:\.

If the calling code comes from the intranet zone, it should not be given
permission to write to the harddrive (because it is in the intranet zone)
and an exception should be thrown when the dll is called.

How can I arrange the web application and the dll on different machines so
that the web application is calling from the intranet zone?

Any help would be gratefully received,

Kerry Whelan