We did this with DS1, and it worked well. However, the "at the door" stage did last for a while! I didn't mind, because at this point he was sleeping through (which was what I was aiming for, rather than self settling for its own sake). We eventually (after a good few weeks) moved to outside the door, with the door open, then outside the door with the door almost closed. Then were able to just walk away. Good luck.
I think we did the bit from the door to outside the door in about 4 days - so at the door with it open, in the doorway, outside with door open, outside with door partly closed and light on outside. It then took a couple of weeks of being outside the door for a few minutes before we would just walk away. By the time we got to the door, like nearlytherenow, my daughter was sleeping through and falling asleep on her own pretty quickly. If he isn't yet settling himself to sleep maybe you need to retreat ever so slightly back in the room for a few more days! I was evangelical about this technique it worked so well for us. Hope you get outside soon!