A signed letter or document for the IRS?

I'd like to create an iTunes Connect account to publish iBooks in your store, after creating them with iBooks Author. You've specified that, in order to create such an iTunes Connect account, I need a U.S. Tax ID. In order to request one from the IRS, I've been requested (by the IRS) to supply, and I quote, "A signed letter or document from the withholding agent, on official letterhead, showing your name and verifying that an ITIN is required to make distributions to you during the current tax year that are subject to IRS information reporting or federal tax withholding."

I'd like to request such a signed letter or document from Apple, but with no luck. What may I do?