Gnome 3, Network-Manager & ifupdown

[David BERCOT <debian bercot org>]

Hello,

I'm a Debian (sid) user under Gnome 3.2.

Because I have many places to configure, I use guessnet
in /etc/network/interfaces. Then, I'd like Network-Manager not to think
I'm not connected, so, I've added :
[ifupdown]
managed=true
in /etc/NetworkManager/NetworkManager.conf

Now, I have two questions :
1. how can I ask Network-Manager to automatically use the connection
choosen in /etc/network/interfaces ? I'd like not to have to click on
the "Ifupdown (myconnection)"...
2. when my wired cable is not connected, how can I do a "basic"
configuration ? Maybe it is in /etc/network/interfaces, but I've tried :
iface eth_disconnected inet manual
	test missing-cable
and it does not work...

Thank you.

David.