This may also be done on a grill.
Preheat oven to 500 degrees. Smear the whole ham with the mustard, then sprinkle the Gateway over it. Sear the ham at 500 degrees for 10 minutes to make a nice crust. Reduce heat to 350 and bake for another 50 minutes. Remove and let rest 10-15 minutes before slicing.
The amount of Gateway and mustard will vary depending on the size of the ham.