In a small bowl, combine the peel and 1 cup water. Let soak for 10 minutes. drain the peel and discard the water.
In an 8-quart pan, combine the peel with the lemon juice, 1 cup water and baking soda. Over medium-high heat, bring to a full boil. Reduce the heat, cover and simmer for 10 minutes, stirring occasionally. Stir in the fruit. Cover and simmer 10 minutes more.
Remove the cover and stir in the sugar and butter. Heat, stirring constantly, until the sugar is completely dissolved.
Increase the heat to medium-high and bring the mixture to a full rolling boil, stirring constantly. Stir in the entire contents of the pectin pouch. Return the mixture to a full rolling boil, stirring constantly. Boil for 1 minute. Remove the pan from the heat and skim off any foam.
To prevent floating fruit, allow the marmalade to cool 5 minutes before filling jars. Gently stir the marmalade to distribute the fruit and ladle the marmalade into hot jars, leaving 1/4-inch headspace. Wipe the jar rims and threads with a clean, damp cloth. Cover with hot lids and apply screw rings. Process half-pint jars in a 200 degree F water bath for 10 minutes, pint jars for 15 minutes.