Welcome to Yorkie Talk. I am sorry to hear Samson has pancreatitis. I haven't been through it personally, but my friends have. I would stick to the prescription food only. Once Samson is back to himself, you could consult a vet dietician like
http://www.petdiets.com for recommendations on safe foods.
Once a dog has had pancreatitis, the dog is at greater risk for life for recurrence. A restricted diet can help prevent another bout.
Sending best wishes for Samson.