I had a C# web solution - I'm using VS.NET 2003 -, let's call it S1, in the directory S1, containing a few web forms and a user control (the user control is a header for each page).

I now need to create a new solution, S2, in a new virtual directory S2, having different requirements - one is that it must use forms authentication.
I understand that in order to allow access to a 'member area', while still having a few pages that can be visited without login, you need to have two projects, so that you have two web.config files:
-one in S2 directory with all forms that do not require authentication
-one in S2/Sub, a 'child' directory of S1, with forms authentication in web.config
I created the two projects, and adding a reference of S2 project to Sub seems to let me navigate from a page in S1 to one in Sub and back.
Is this the correct approach?

Now I would like to reuse the user control I created in S1, but I don't want references back to S1 in my new S2. I tried to add it as an existing item, or plain copy of files and bin directory, regardless, I can see references to S1.
The user control is not very complex, so I created it from scratch in S2. That allows to add it to all forms in S1, but I cant add it to forms in Sub! If I do, I get the following error:

Parser Error Message: The virtual path '/S2/ph.ascx' maps to another application, which is not allowed.
Source Error:
Line 1: lt%@ Page language="c#" Codebehind="dzm.aspx.cs" AutoEventWireup="false" Inherits="dzm.WebForm1" %gt
Line 2: lt%@ Register TagPrefix="uc1" TagName="ph" Src="../ph.ascx" %gt
Line 3: lt!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" %gt
Line 4: ltHTMLgt

Do I need to create the user control in each project?? I doubt it... but can't figure out how else to do it.

TIA