Actually there is a workaround, but I would *much* rather that "Navigate from Maps" be made to work properly in iOS 6. Anyone have any information on if it's being ported? Anyways, here is the workaround:
In their latest release that came out this week, Navigon took advantage of a gaping whole in iOS 6 Maps and not only offer public transit info (with a $2.99 in-app purchase), but even lets you use Siri/Maps to find the location you want to Navigate to and then hand it off to Navigon to give you the “professional” navigation and turn-by-turn directions you are looking for. While this feature is cool, it may not last forever. If Apple adds public transit stuff, then this feature in Navigon (the hand off) could easily stop working, but for now it’s there if you need it.
Find the address, POI that you want to navigate to on Maps
Tap the pin to be taken to the information page about that location.
Tap the “Directions to Here” button
Tap the Bus icon and the Route button
Since Apple doesn’t offer this routing it will prompt you with Apps that do, including your Navigon App
Tap the Route button next to Navigon
Once you’re in the Navigon App you can choose to route via your vehicle or public transportation