From my experience no, there isnt a way to do it... all my bribes at Junker bases were reversed back to the original due to the repninja... (i really hate that!!! the most stupid idea was to implement that thing on server)
As mentioned above you have only chance to trade with a Junker ID (and not to get blown up by bomber patrols in seconds with your whole cargo) I used for that purpose the /restart Gallia command and then i have set up the Junker char.