I once thought about making my own enchilada sauce. When I was at the store I looked on the can of prepared enchilada sauce (red sauce) I saw pasilla peppers, vegetable oil, and vinegar as the three main ingredients. A little salt too. I tried this using dried pasillas. I boiled them until they were soft and then slit them and scraped the softened slightly pasty insides of them into a stainless steel pan with the salt, oil and vinegar. This I mixed together and wow it made great enchilada sauce. The paste from the peppers seems to emulsify the oil and vinegar together as well as giving the resulting sauce a very good flavor. You will need at least 4 whole dried pasilla peppers as well as oil and vinegar in a 3 to 1 ratio(3/4 cup oil to 1/4 cup vinegar.) Add 1/2 tsp salt to this and you're good to go. I don't know about the green enchilada sauce but it seems like you could look on a can of it to find out the ingredients.

Viv in Springfield