Go to this article...

http://msdn2.microsoft.com/en-us/library/ms998258.aspx#pagguidelines0001_imperso
nationdelegation

and go to a section about two thirds down called ...

Avoid Losing Impersonation Tokens

I think it is exactly what you are after.

Hope that helps.

maa,

I think this will take care of what you're looking for. It's an excerpt from
the MSDN article found here:
http://support.microsoft.com/kb/306158

Impersonate the Authenticating User in Code
To impersonate the authenticating user (User.Identity) only when you run a
particular section of code, you can use the code to follow. This method
requires that the authenticating user identity is of type WindowsIdentity.

Visual Basic .NET
Dim impersonationContext As
System.Security.Principal.WindowsImpersonationContext
Dim currentWindowsIdentity As System.Security.Principal.WindowsIdentity

currentWindowsIdentity = CType(User.Identity,
System.Security.Principal.WindowsIdentity)
impersonationContext = currentWindowsIdentity.Impersonate()

'Insert your code that runs under the security context of the authenticating
user here.

impersonationContext.Undo()

Visual C# .NET
System.Security.Principal.WindowsImpersonationContext impersonationContext;
impersonationContext =
   ((System.Security.Principal.WindowsIdentity)User.Identity).Impersonate();

//Insert your code that runs under the security context of the
authenticating user here.

impersonationContext.Undo();

Regards,

S. Justin Gengo, MCP

Free code and component libraries at:
http://www.aboutfortunate.com