Hello Sander,
The block "cart sidebar" is recognized by class name "Mage_Checkout_Block_Cart_Sidebar". This block is really represented type "checkout/cart_sidebar" in layout. System watches creating blocks. In time of creating specified blocks are replaced special blocks; insantces of Artio_MTurbo_Block_Ajax, which prints special div container into html. Browser then loaded blocks by Ajax and puts them into special created containers.
If you lost cart menu, then the javascript probably fails. Check that in the head of your html is placed javascript "skin/frontend/default/default/js/mturbo.js", please. If not, it's possible that you use another design package. In this case, copy that javascript into path which will respect your design package.
If javascript is loaded or instructions described above doesn't help you, then you try to make follows test. You put into your browser follows url: YOUR_SITE/mturbo?identifier[]=cartsidebar. If you see information about cart, then javascript isn't working. If you see nothing, then mturbo ajax handler isn't working. In this case contact us by email (
info@artio.czDiese E-Mail-Adresse ist gegen Spambots geschützt! Du musst JavaScript aktivieren, damit Du sie sehen kannst.
or
jiri.chmiel@artio.czDiese E-Mail-Adresse ist gegen Spambots geschützt! Du musst JavaScript aktivieren, damit Du sie sehen kannst.
). We will look at issue more deeply.