how to set user propertyes for an encrypted (win2k 2k3) with vb.net?

From: Alessandro Belli (alessandro_at_micateladico.it)
Date: 02/24/04 

Date: Tue, 24 Feb 2004 12:41:24 +0100

I need to add more user to the list of user that has ability to
encrypt-decrypt a file, under XP-2k3.
In other terms, to do by software the same as you can do if under file>
property> advanced> encryption > details, where you can set many users to
use the same encrypted file.
Is there anything inside the framework I can use to do this, without use the
API?
Thank you.
Alessandro