vCloud Retrieve allocated externat IP

Hello,


Using the vcloud JAVA SDK v5.1, I've created a vApp with one vApp network.


I had attached a VM to this Network.


After starting this vApp:


I succeed to retrieve the VM's private address:


cmd:VM1.getNetworkConnections().iterator().next().getExternalIpAddress()


But while trying to retrieve the VM's public address I get always a null String :


 VM1.getNetworkConnections().iterator().next().getExternalIpAddress()


Although, I see on dashboard that it allocated to this VM an external IP.


Any one have an idea?


Many thanks,


Béchir