Questions about network credentials...

I've been looking and googling for a while and I'm not finding what I need...

1) Is it possible to remove the "Remember me" checkbox from the network logon dialog?
(There was a tweak for this in Win2000 but it doesn't seem to work in Win7)




2) Is there a way to close a network connection?
That is, I want to be able to "logoff" a network share and reconnect under different credentials. It would also be nice if it closed the connection whenever I lock the desktop or log off my user account...