BigIP 4000 Howto export Private Key through cli tmsh commands

A BigIP 4000 was installed with "common criteria mode" enabled similar to appliance mode. I need to restore the equipment but previously I want to export the digital certificates and private keys installed. With my administrator user I can export the certificates but it does not allow me to export the keys through the GUI. Is there a procedure to export the keys through tmsh? My user does not have bash.