Hello Big Al,
Mortadella is a cooked sausage made quite differently from dry fermented types of sausage. In fact the only similarity is they both have meat as main ingredient. To our knowledge, real Italian Mortadella is not fermented or aged and the meat has to be made into an emulsion with chunks of pork fat and sometimes pistachios mixed in at the end. You can probably use UMAi Dry casing to make it, but we have never tried doing this, so if you end up doing this please share your results.
Here is a link to a recipe by our favorite Stanley Marianski: http://www.meatsandsausages.com/sausage-recipes/mortadella-bologna