Been flying a CJ2 for 5 years and the only way to display DME is to have NAV as the active nav selection.
If you only have a single DME then holding the DME will display it on both PFD's if both are selected to NAV.
In this machine there is a DME repeater under the PFD that displays either NAV1 or NAV2 DME but I guess it's an optional extra.