Error when trying to access nm with vala and gdbus

[Florent Thévenet <feuloren free fr>]

Hi everyone,

I'm writing a program to change the evolution smtp server according to
the network I'm connected to, implemented in Vala

The simpler solution I found to talk to networkmanager is over dbus,
here is the code I use:

"""
[DBus (name = "org.freedesktop.NetworkManager")]
interface NetworkManager : Object {
	[DBus (name = "state")]
	public abstract uint state () throws IOError;
	public signal void state_changed(uint state);
}

[DBus (name = "org.freedesktop.NetworkManager.Settings.Connection")]
interface Connection : Object {
	public abstract HashTable<string, HashTable<string, Variant>>
get_settings() throws IOError; 
}

[DBus (name = "org.freedesktop.NetworkManager.Connection.Active")]
interface NetworkManagerActiveConnection : Object {
}

void main() {
	var loop = new MainLoop();
    //watch state change

	//get connection infos

	//get active connection
	NetworkManager nm;
	Connection conn;

	nm = Bus.get_proxy_sync(BusType.SYSTEM,
"org.freedesktop.NetworkManager", "/org/freedesktop/NetworkManager");
	nm.state_changed.connect((s) => {
			stdout.printf("state changed : %d\n", s);
		});

	conn = Bus.get_proxy_sync(BusType.SYSTEM,
"org.freedesktop.NetworkManager.Settings.Connection",
"/org/freedesktop/NetworkManager/Settings/15");

	var result = conn.get_settings();
	var v = result.get("connection").get("id");
	stdout.printf("%u\n%s", nm.state(), v.get_string());

	loop.run();
}
"""

The signal part works great, but I get an error when trying to get a
proxy for org.freedesktop.NetworkManager.Settings.Connection:

"""
** (process:4271): CRITICAL **:
file /home/florent/Projets/smtp_switcher/nm_detection.vala.c: line 747:
unexpected error: GDBus.Error:org.freedesktop.DBus.Error.ServiceUnknown:
The name org.freedesktop.NetworkManager.Settings.Connection was not
provided by any .service files (g-dbus-error-quark, 2)
"""

I'm using ubuntu 11.10, is there a solution or direct Vala bindings for
NetworkManager ?

Cheers
Florent