sql safe backup File\Filegroups

Selecting *Backup* from the top left menu option - allows for a one time backup

Full, Differential, Log and File are the choices.

However, if you create a policy - you only have Full, Differential, and Log. 

The "File" option (where you can choose which File\Filegroups you want to backup) is missing.

You *can* check a box to backup Read-Only filegroups, but that's not what I need.

We need the same options when creating a Policy (that can be scheduled), that

we have in the One-time Backup option (top left menu).

Thanks!