This feature was always available if you create your own balance query from the query tab. There you can specify until which charge date you want to include in the future credit card calculation.
Have now also added this to the statement tab. You just need to enter a date next to the "Deduct Future CC Transactions" check box. (2)
Also added option to calculate the balance to the end of the year even if you are only displaying until today. Just enter a date next to the "Account with Balance >" box. (1)