If you go into 'my profile' (top of the page in the header) then scroll down you'll find 'my rig'. On the right hand side there should be a clicky to create a new rig. Just fill in the details, you'll be able to search for products you use and match them.
Then go to 'edit signature' (same page you clicked 'create rig'). At the bottom of the pop up window there should be an option to show off stuff in your sig, select your rig.
It should then display in the bottom of your sig when you post. (just like mine and most others)
Edited by Doug2507 - 10/18/13 at 4:25am