Place lemon peel and pulp in a pot with just enough water to cover. Bring to a boil and simmer 5 minutes. Turn off heat; cover with a lid and let sit for 12 to 18 hours. Drain water. Combine lemon peel and pulp, strawberries, pectin, and lemon juice in a large pot. Bring to a boil. Add sugar, stirring until dissolved. Bring to a rolling boil. Boil hard 1 minute, stirring constantly. Remove from heat. Skim foam if necessary. (I add a bit of butter to prevent foam.) Ladle hot marmalade into jars, leaving 1/4-inch headspace. Adjust two-piece caps. BWB 10 minutes.