WARNING: This page is about a different car, the 2012 BMW 328i, 2011 BMW 328i, 2010 BMW 328i, and 2009 BMW 328i. However, it is still accessible from the selected car via links, so may be relevant.
TIGHTENING TORQUE SPECIFICATIONS - ELECTRONIC POWER STEERING
Type
Thread
Tightening specification
Measure
1AZ Retaining plate, active front steering control unit to body