The custodian combining these two distributions on a single (probably code 7) Form 1099-R is correct. As long as you did not roll over any part of this to another traditional IRA, you can enter this as a single Form 1099-R, indicate that you moved the money to another retirement account, that you did a combination of transactions and indicate the amount that was converted to Roth. The remainder will be treated as a distribution not rolled over. If you did do a combination of rolling over and converting, you will need to split the Form 1099-R as you have done.
