Net bridges are not made automatically, you have to manually place them where you want to join copper areas. The usual step is that a user will create or separate copper areas, then they can decide what type of net bridge they want to use and exactly where. It is treated as a real component that needs a specific position and type, depending on your design constraints.
Jumpers, in the other hand, are not real components (and I'm speaking as how the software looks at it), you would use autoroute first, and then do traces manually, and then you would use jumpers depending on how the design goes. If you run autorouter again it will try to look for a route for that trace therefore discarding the need for a jumper. I would say that it would be nice to have a setting on the jumper as to consider it a real component. So, if you are looking to have a jumper as a real component, I would recommend you to add one (create a custom component) to your database, that you could use on your designs.
Bear in mind I haven't use Ultiboard that much but I have a theory after reading this that might work but not quite sure. I will pose it as a question: Couldn't you use a Zero ohm resistor to minimic a jumper? That way it would be treated as a real component. I know that Multisim has them but I am not sure about Ultiboard. recognizing them.
In my theory you could autoroute and find where you need these jumpers and edit the schematic to place them and run your wires to them. That way when it is transfered they will be placed like any other component and routed. This is just a theory and may not be possible or will solve the problem, but I thought I say something just in case it is a workable solution.
Thanks for your feedback to both of you, be assured that it has been entered in the Feature Request list so we can discuss the possibility of this.