IIS 6 Windows Authentication + ASP.NET Impersonation when application resides on a UNC share

When the application resides on a local folder, the current user ((System.Threading.Thread.CurrentPrincipal.Identity.Name) is the windows authenticated user. OK.
But..when the application resides on a UNC share, the current user is the windows user configured in IIS virtual directory to access the UNC share. This is not the desired behavior in my case, what I want is to have the same behavior as in the case where the application is in a local folder (current user matches the windows authenticated user)
This is configurable in some way in IIS 6 or IIS 7?
 
thanks in advance,
Alexander Wolff
 
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