howto: vb.net set group rights to a network file

Question

Hello:
using whidbey, vb.net,
I am impersonating a domain admin
I have retrieved from AD a group called: "oci\School Reporting Authentication:
I call the following:
1) I impersonate a domain admin
2) I open a dialog box and go to the file on the win 2003 server that the Impersonated account has admin rights on
3) I call the following
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Dim user As String = "oci\School Reporting Authentication"
Dim mSec As New EventWaitHandleSecurity()
Dim rule = New EventWaitHandleAccessRule(user, EventWaitHandleRights.ReadPermissions, AccessControlType.Allow)
Try
   mSec.AddAccessRule(rule)
Catch ex As Security.Authentication.InvalidCredentialException

Form1.lblFilename.Text = Form1.lblFilename.Text + vbCrLf + "exception assigning rule:" + ex.Message
End Try

Form1.lblFilename.Text = Form1.lblFilename.Text + vbCrLf + "Are access Rules Protected ?:" + mSec.AreAccessRulesProtected.ToString()

mSec = Nothing
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There are no errors and the new group "wont take" - nothing happens.

Question: is this approach using EventWaitHandleSecurity() correct or is there a better one?
Thanks
Support