In a medium bowl, mix together the soy sauce, marmalade, barbeque sauce, garlic, mustard, horseradish and salt.
One at a time, dunk rib pieces into sauce, being sure they are fully covered with the sauce, and place into a 4-quart crock-pot, meaty side up. After all the ribs are in the crock-pot, pour the remaining barbeque sauce over the ribs; place lid on crock-pot.
Heat on high for 20 minutes; lower heat to low and cook for 6 hours. Remove ribs from crock-pot to serving platter; keep warm.
Place about 1/4 cup of barbeque sauce into a small heat-proof bowl, whisk in the cornstarch. Place the remaining barbeque sauce into a medium saucepan; add in the barbeque sauce/cornstarch mixture. Heat on high until barbeque sauce boils, lower heat to medium-low and cook for 3 - 5 minutes until thickened.
Serve ribs with barbeque sauce on the side.
Notes: Time on high 20 minutes
Time on low 6 hours