After further testing, the Vehicle Roboport does not seem to work. I'll look into it, and hope I can fix it before you get home! :)
Edit: This seems to be on purpose. After "Fixing" it (by allow it to use all equipment regardless of anything), I noticed that only the Car, the Tank, and the Locomotives was allowed to use it (not even the other Bob's Vehicles, like the Cargo Wagon), and it was only "Vehicle Roboport", "Vehicle Overdrive Motor" and "Vehicle Overdrive Engine" that had this restriction. - I think I will leave it be. Besides, there are alternatives for all of those in the game already ("Personal Roboport" and "Afterburner" respectively)