I have copied the following from this article as I think it might be relevant:
http://www.2ndchance.info/pancreatitisdog.htmThe Chronic Form Of Pancreatitis
"Repeated bouts of acute pancreatic attacks eventually destroy the organs ability to produce digestive enzymes.
You might observe recurrent bouts of cramping, abdominal pain and tenderness, arched back, reluctance to move, little or no appetite and transient depression over an extended period as your pet journeys into the chronic form of pancreatitis.
Once these changes occur, the pancreas cannot regain its healthy state. In those pet, veterinarians will attempt to lessen your pet’s need for the missing enzymes (through special diets) and supplement the missing enzymes with similar enzymes available in powder or tablet form.
Sometimes, it is not only the enzyme-producing tissue within the pancreas that is lost. The portion producing insulin can also be lost, leading to diabetes.
I have noticed that stool color and consistency often change as pets pass into the chronic stage of pancreatitis. It tends to be a lighter yellowish or clay color, smell worse, and have a greasy appearance.This is because of a lack of pancreatic enzyme (pancreatic lipase) necessary to digest, emulsify and absorb fatty substances in your pet's diet. (similar stool changes occur when a pet’s liver no longer produces sufficient bile)
Because these pets are starved for nutrients, they tend to gradually loose weight no matter how much they eat."It sounds as if your boy might have chronic pancreatitis. Having nearly lost Dickon to this I am a bit over cautious perhaps, but I am a bit concerned your vet doesn't seem to be taking it very seriously? I would be taking him back for more tests sooner rather than later.