I have never successfully done this, I tried several times and the same thing would happen - DS would wake up screaming and was then impossible to resettle. I ended up doing what Beckoes did - sitting in the car with the engine running for up to 2 hours so DS could get his sleep. It was a bit annoying, but I did get a lot of reading done! Now I just stay home in the mornings so that I am home when nap time comes around.

Sorry I can't help!!