Forcing them is not the right thing to do.

I am a Shimano user but here is my understanding from what I have seen people doing. Campy don't have a cam type quick release on the calipers but a quick release mech built into the lever. On Veloce I think I remember a pin on the inside of the lever. You pull the brake lever a little then press in then pin, when you release the lever it allows the calipers to open wider than normal.

Hope that helps

(edit cuski beat me to it but his link isn't working for me)