You are using Visual Studio 2008 to upgrade a Visual Studio 2005 ASP.NET project that used Web Service Enhancements 3.0 (WSE 3.0). After upgrading, the secured reference is missing.
Keep a copy of your old project.
After upgrading your project, open the old project in Visual Studio 2005.
Select "Show All Files" in Solution Explorer, then drill down into "Web References," then your WSE web reference, then Reference.map and finally into Reference.cs or Reference.vb, depending on your language of choice.
There will be two classes in here. The Wse class (which was removed by the VS2008 upgrade) will be at the top of the file. Copy that class into the same file in your VS2008 project.