How To Use CLR Security ..Impersonation To Access External Resources?

I want to Access External resources inside the CLR Code... But I am getting Security Exception

I have marked Assembly with External Access... here is the way I am doing..

I read articles and MSDN .. everywhere is written to use impersonation like

using (WindowsIdentity id = SqlContext.WindowsIdentity)

{

WindowsImpersonationContext c = id.Impersonate();

//perform operations with external resources and then undo

c.Undo();

}

In above case .. I tried both Windows Authentications and SQL Authentications ...

In case of Windows.. I am have a domain login to logon to my pc, while sql server is at another machine and Active directory is at different machine .. when connect to Database .. it says cannot find user Domainnameuser

and the SqlContext.WindowsIdentity is always null or it has exception User.Toked thew Security exception.



After that .. I tried to user custome Identity .. using IIdentity =GenericIdentity("UserName","Windows");

But there is now difference .. still same exception .. as given below..

[Microsoft.SqlServer.Server.SqlProcedure]

public static void MyProcedure()

{

Process[] p = Process.GetProcessesByName("YPager"); //Yahoo messanger exe .. a process

p[0].kill();

}

A .NET Framework error occurred during execution of user defined routine or aggregate 'MyProcedure': System.Security.SecurityException: Request failed.

System.Security.SecurityException:

at System.Security.CodeAccessSecurityEngine.ThrowSecurityException(Assembly asm, PermissionSet granted, PermissionSet refused, RuntimeMethodHandle rmh, SecurityAction action, Object demand, IPermission permThatFailed)

at System.Security.CodeAccessSecurityEngine.ThrowSecurityException(Object assemblyOrString, PermissionSet granted, PermissionSet refused, RuntimeMethodHandle rmh, SecurityAction action, Object demand, IPermission permThatFailed)

at System.Security.CodeAccessSecurityEngine.CheckSetHelper(PermissionSet grants, PermissionSet refused, PermissionSet demands, RuntimeMethodHandle rmh, Object assemblyOrString, SecurityAction action, Boolean throwException)

at System.Security.CodeAccessSecurityEngine.CheckSetHelper(CompressedStack cs, PermissionSet grants, PermissionSet refused, PermissionSet demands, RuntimeMethodHandle rmh, Assembly asm, SecurityAction action)

at DatFileGenerator.StoredProcedures.'MyProcedure'()

.

No rows affected.

(0 row(s) returned)

@RETURN_VALUE =

Finished running [dbo].['MyProcedure'].



How could I go ahead... what I should do to accompilsh the task...

Kindlly .. suggestions and ideas..

Thanks,

Muna