Testifyer, try modifying my letter (can be found on Sample Letter for HB sticky) or at my website, JulianArts.com. First, be sure to look up Indiana law on insurance coverage so that you can quote it in your letter. Most letters (from what i have learned) are turned down b/c momma's try to convince the insurance co that HB is safer, better, more practical...whatever personal story they share usually just ends them up in the denial pile.
What the insurance company wants is run down of what you are asking for: coverage at the full benefit level for out-of-network providers...or coverage for a specialist service...whatever. I included a referral from an In-Network provider who stated that she could NOT do HB,and didn't know anyone in our area who did, a copy of the law in my state that says that if the service i need is not available in my network, that i must be allowed to access those services as long as the provider is a legal provider in my state (CNM's can do HB here as long as they have a written practice agreement with an OB).
Along with the approval, they also included a section that stated that they do not check the credentials of out of network providers, that they have no way to promise me that my HB MW would have liability insurance, and that they were concerned about the level of newborn care available at HB setting. But they still approved me, they just put their "disclaimer" out there to cover their butts.
Good luck!