Navigation Frustration

When I bought my Prius (two days ago) I thought I tried all of the bells and whistles at the showroom. Today my husband was driving and I needed to enter an address in the navigator. The Salesman showed me how to do it, but I couldn't get it to work. I finally resorted to my handy smartphone. Through lunch, my husband read the handbook, with no luck. When we got home and put the car in Park, we saw the "Address" key light up! I called my salesman who explained that it was a safety feature, so the driver won't be tempted to use it while driving. I told him that I was the passenger! He said that the navigator couldn't tell the difference.

Does anyone know a way around this? We are often together and I'd like to be able to use the navigator for spontaneous trips without pulling off the freeway. Thank you.