Two Nodes, Unicast Cluster with 3.1

Hi,

I'm trying to setup cleanly a two nodes unicast cluster with version 3.1 as I only want centralised controle and VM/CT migrations.
I had already done this with version 2.3 (don't remember exactly the steps) but it seems to be a little bit different with 3.1.
Here are the steps I used:

- Install a new Proxmox 3.1 server
- pvecm create <cluster name>
- cp /etc/pve/cluster.conf /etc/pve/cluster.conf.new
- nano /etc/pve/cluster.conf.new:
<?xml version="1.0"?><cluster name="clustername" config_version="2">
<cman keyfile="/var/lib/pve-cluster/corosync.authkey" transport="udpu" two_node="1" expected_votes="1">
</cman>
<clusternodes>
<clusternode name="proxmoxserver1" votes="1" nodeid="1"/>
</clusternodes>
</cluster>
- Than I activate the new configuration via the Web interface/HA

That seems to be ok but if I do service cman restart, I get:

Starting cman... two_node set but there are more than 2 nodescman_tool: corosync daemon didn't start Check cluster logs for details

Then I cannot modify the cluster.conf anymore.
The only way I've found to go back is to destroy the cluster
sudo /etc/init.d/pve-cluster stop
sudo /etc/init.d/cman stop
sudo rm /etc/cluster/cluster.conf
sudo rm -rf /var/lib/pve-cluster/*
sudo /etc/init.d/pve-cluster start

Is there a better way to go back in case of error?
Must I need two add the other node before set the two_node="1" option?
Is there some clear documentation somewhere that explain how to do this for 3.1?