Is this possible: deploying a machine to Rackspace with only a private network?

Hi,

Can anyone tell me whether this is possible please?

I'd like to deploy to Rackspace a VM which only a network connection to a
custom network, rather than the PublicNet and ServiceNet interfaces.
At the moment when I deploy via Foreman I don't seem to have the option to
choose from a list of networks to which my VM can connect.

I can deploy this kind of machine via the Rackspace Cloud web interface and
I have also been able to do the same with the 'nova' command-line client,
but at the moment I'm unable to do this via Foreman.
I have set up an edge router with a VPN initiator in this private network,
so I also need to set both default route and DNS settings for each host,
but that's a separate issue. FOr the moment it would just be good if I
could get the image deployment and the DNS smart proxy to work from within
Foreman for these hosts.

If anyone has any insight or suggestions on how I could get this to work,
I'd appreciate it.

Kind regards,
Ben