A JumpBox comes with two VMWare GSX-like disk images: disks/root/root.vmdk, and disks/data/data.vmdk. ESX includes a command line tool, available on your ESX server's maintenance console, called vmkfstools. This tool can be used to import the JumpBox disk images into your ESX server. The process is described in http://kb.vmware.com/kb/900 at the bottom of the page where it mentions Importing GSX Server and Workstation Virtual Disks to ESX Server.

Once the disk files are imported, you can create a new virtual machine using those disk images. Ensure that you allocate at least 256MB of RAM and add a network card. It may also be possible for you to navigate to the JumpBox.vmx file that came with your JumpBox and right click on it and choose "Add to Inventory".

Additional discussion can be found in this JumpBox forum thread or by searching the JumpBox forums.