SoftLayer has a private network which is accessible only via VPN. It took me a really long time to figure out how to connect on Ubuntu 12.04 running on VirtualBox.
To configure the VPN connection, from the network manager icon in the top right corner click: “VPN Connections” > “Configure VPN…”. Use a PPTP VPN, enter the gateway, set the username and password, and then under “Advanced…” uncheck all the authentication methods except MSCHAPv2 and check “Use Point-to-Point encryption (MPPE)”
If you’re running under VirtualBox then you’ll need to update the “Network” tab to use the attached to “Bridged Adapter” setting instead of the default “NAT”.