Pre tax 401k rollover to Roth

I rolled my company's pretax 401K balance to a Roth IRA.  The trustee issued a 1099r showing zero taxable in box 2a and code G in box 7.  I asked the trustee to issue a corrected 1099r with the full amount in box 2a and distribution code 2 in box 7 and they refused.  I keep getting advice to not change the fields from the 1099r while entering in TurboTax.  So how do I record this information in TurboTax so that I pay the appropriate tax on the conversion?  I have gone through the questionnaire on what I did with the money and selected the radio button that I put it in a Roth, but the tax due is not updating.