WARNING: This page is about a different car, the 2010 Porsche Cayenne, 2009 Porsche Cayenne, and 2008 Porsche Cayenne. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Locating Countershaft Cap
Courtesy of PORSCHE CARS NORTH AMERICA, INC.
Drive new cap in flush using special tool pressure piece t10180.