Mix mustard, vinegar, brown sugar, lemon juice, Worcestershire sauce, cayenne pepper and olive oil well. Bring to a boil and then turn down heat and simmer for 30 minutes. Pour into container and let sit in refrigerator over night. Cook pork roast in crock pot until it falls apart. Salt and pepper to tasted. Remove roast from crock pot and place in a shallow baking dish. With two forks shred the roast well and discard any fat globules. Pour 1/2 the bbq sauce over the meat and put in 300º oven for about 1 hour. Put remainder of bbq sauce in a bottle as use on pork as desired.