Change Windows User to have new rights

Question

Hi !! I've got a problem on an windows application in C# My connection are made with the Windows Users parameters. And they give an number of rights over my I/O System. But for a spécific function, i need to change this users to have rights on an other directory. I know that there is a class Impersonation but it seems to work only over XP. And i need to make that on Win 2000 station. Does anybody know, how to make that ??? Thanks.