Shimano auto-4 change km/hr to mph?

I (my wife) has a 2004 Bianchi Auto-Milano with a Shimano Nexus Auto-D 4 speed hub. The speedo reeds in km/hr and I want to change it to mph. I downloaded a manual which said to follow steps 1-4 on page 15 first then do .... The manual is 8 pages long and page 15 is in the manual for the dealer. Can anyone tell me what steps I need to follow to change the readout, besides multiplying reading by 0.62.

Thanks in advance. John