Looking for a part for my CBR1000rr

Hi Guys:

I just found out that the revervoir cap that goes on the rear shock absorber of my CBR1000rr is missing. I checked the dealer, and they don't even have a part number for it - strange. The manual refers to it as rear "Shock Absorber Reservoir Cap". Anybody know where I can get a replacement?

Thanks for your help.

    if you can buy it
it will be on this picture
http://fiche.ronayers.com/Index.cfm/Module/Main/TypeID/4/Type/Sportbike/MakeID/1/Make/Honda/YearID/45/Year/2004/ModelID/7407/Model/CBR1000RR/GroupID/324011/Group/REAR_SHOCK_ABSORBER