I do not think the E90 or E92 offers the option of programming the multi function steering wheel buttons. I know in my E60 this could be done. There are no "star" or "diamond" buttons on the E90 or E92.
The DLR can be switched on/off without iDrive via the control on the indicator stalk. The menu options for this are shown in the OBC display on the dash...check out your driver manual.
E91 335i M Sport