The only other reasons that I can think of that TurboTax would not give you the opportunity to indicate that the distribution was transferred to charity is if you entered the Form 1099-R as belonging to you spouse, if younger, or if you have entered your birthdate incorrectly in the personal information.
If you are using the CD/download version, make sure that you have installed the latest update.
If you are using the online version, to indicate that you had some or all of the money transferred to charity you must mark the corresponding box on the Do any of these situations apply to you page.
