If its all still done the same, flames will show up in your item.dat file in the custom folder when you have them active.
Go there, open it up and copy the line about the flame. There was a thread that had instructions on how to interpret those numbers to translate them into what was needed for the forge. Ill see if I can find that thread for you.
edit: Hmm, cant seem to find it. Im fairly sure all the values go in the same order from item.dat and the forge. So first number from item.dat in the top spot for forge and so on.
Last edited by Gum; Jul 17, 2015 at 07:46 AM.