How to : Convert Jumbox to OVF
Extract your previously downloaded Jumbox to a folder
Download VMware OVF Tool from here : http://communities.vmware.com/community/vmtn/vsphere/automationtools/ovf
Install the OVF tool
Run the OVF tool with the following options
ovftool /yourjumbox/JumpBox.vmx /folder/foryourovf
Just wait for the transfer to be done and you will be ready to import your Jumbox in vSphere or VirtualBox.
To see all option use :
ovftool --help