Log Out Button - how to create

-- url of the page with the problem -- : www.a-cutabove.co.uk
-- HikaShop version -- : 2.2.3
-- Joomla version -- : 3.2.2
-- PHP version -- : 5.4.28
-- Browser(s) name and version -- : XXXXX x.x.x
-- Error-message(debug-mod must be tuned on) -- : Error_message

I have been experimenting on creating a logout button to registerred users and cant make the link return to the home page after log out.
I have tried this as an extermnal link on a hikashop menu item?
index.php?option=com_user&task=logout&return=Lw

Hello,
Note that the best solution will probably just be to use a Joomla login module which will display a logout button.