see link. https://accountants.intuit.com/community/proseries-tax-discussions/discussion/how-do-i-do-a-back-doo...

Use the IRA contribution worksheet, don't enter directly on the 8606, assuming it IS non-deductible, the software will put the figures needed on the 8606 automatically. 

Then when you enter the 1099R (and mark it on page 2 as a roth conversion) it will pick up the non-deductible IRA contribution from the 8606 and make the distribution non-taxable.