Looking for a train from Beijing to Datong with a late departure (soft sleeper)

Hi there, I'm looking for a night train from Beijing to Datong on the 23rd of September with a late departure (between 22 to midnight). In your web I've seen a couple of night trains, but none of them offer a soft sleeper, they do offer just hard or soft seats... could you please confirm if there is any train that meets my requirements? Thanks in advance for your help!