I think that what the people who want to get a paternity test for the baby should do is claim that Anna Nicole Smith's baby is really dead and Howard K. Stern has replaced her with another baby. At that point, they can demand DNA tests to determine the maternity of the baby or else the baby and her guardian have no standing to inherit any of Anna Nicole's assets in the U.S. or to continue Ms. Smith's suits for cash from her late husband.
In other words, if Mr. Stern really is in it for the cash, make the baby worthless unless they get a DNA sample. That sample can then, of course, be used to establish paternity as well as maternity.
That is all.