"Create new wireless network" not available

Hi!

I'm using Lucid on a Lenovo ThinkPad and trying to set up my laptop so that other wireless devices can use its ethernet connection. Various tutorials I've seen on line say that, by left-clicking on the Network Manager, you then select "Create new wireless network". However, neither that option, nor the hidden-network option appear on the drop-down menu. Can anyone suggest why this is happening?

Thanks,

Gareth.