alpac,
check out these link, even though it in not for an X5, it should give you a pretty good idea and it also discusses about a seperator tool,

Thrust Arm Replacement 1997-2003 5-SERIES V-8 CARS - Bimmerforums - The Ultimate BMW Forum

DIY - Powerflex thrust arm bushings - bimmerfest - BMW Forums

- Harbor Freight Tools - Quality Tools at the Lowest Prices

- Harbor Freight Tools - Quality Tools at the Lowest Prices