Build date from 09/2001:

Remove turn signal lamp. See 63 13 150 REMOVING AND INSTALLING/REPLACING COMPLETE FRONT LEFT OR RIGHT TURN SIGNAL LAMP

Version with headlight cleaning system:

Remove jet nozzle of headlight cleaning system. See 61 67 045 REMOVING AND INSTALLING/REPLACING SPRAY NOZZLES FOR LEFT OR RIGHT HEADLIGHT CLEANING SYSTEM

Press detent lug (1) and feed out trim (2) in direction of arrow.

Fig 1: Pressing Detent Lug

Courtesy of BMW OF NORTH AMERICA, INC.

Press detent lugs (1) and remove trim (2) in direction of arrow.

Installation: 

Make sure bonded seal (3) is correctly seated.

Fig 2: Pressing Detent Lugs & Removing Trim

Courtesy of BMW OF NORTH AMERICA, INC.