My company does the same thing...hey, we might all work for the same company!
Anyway...the instructions with the pedometer they gave us say to put it on your shoe when you bike. So I do. On my 13.5 mile (one way) commute, I avg about 18mph. I think it registers between 4500 and 5000 steps for the ride. Eh...dont' really care. I'm kind of tired of wearing the stupid pedometer around anyway.