No, synth discussion is not permitted anywhere on BL. OP-Google is your friend here, but ordering acetic anhydride is not very smart anyway. Enjoy your morphine like it is and avoid a lengthy prison sentence.
Morphine base + pyridine & acetic anhydride. Extract and convert to hcl erowid has exactly what you want. Acetic anhydride is used in photography, too...
I know people in australia and new zealand do something referred to as "homebake" which is a poor attempt at making pure diacytl, but like everyone else said, google is god. it knows all.
Yields are always less than the theoretical anyway, especially when doing very small reactions. I have a feeling the loss of product in most situations with some morphine pills would leave you at a net loss or close to it, even allowing for the difference in potency.