Ernie -
the key to insurance coverage in most cases is to tell your insurance company that a BAHA isn't a hearing aid - it's an implant. That is the truth, and it is what generally gets it covered by insurance. Most - but not all - insurance policies don't cover conventional hearing aids.
It is VITAL that you educate them, since most insurance companies - and even most doctors - don't know what a BAHA is. It will also help to tell them that BAHAs are covered by Medicare/Medicaid, are considered medically necessary, and are in NO way experimental.
Also, if your insurance company covers Cochlear implants, you have a good case for getting them to cover a BAHA. A BAHA is to unilaterally deaf people (SSD) what a Cochlear is to bilaterally deaf people (deafness in both ears).
Your doctor and his staff are used to "fighting" insurance companies for coverage, so make sure you have them help you in your request for coverage.
And, if you are turned down, don't take no for an answer. From what the ANA tells me, most BAHA requests are turned down the first time, but if you pursue it you will succeed.
Good luck,
Jan