Just go with "sir" and then the "velo" from "VeloNews". That's how you pronounce it in English. Why? Because we say so, never mind the accent aigu on the e. English doesn't have the accent aigu, so why pay attention to it. If you're talking about Cervelo in French on the other hand, you'd better honor the accent.
http://forum.slowtwitch.com/cgi-bin/gforum.cgi?post=62128#62128
From the horse's mouth.