You will need to follow the example of how to the example for adding a login block to the header
http://www.viart.com/add_blocks_into_header.html
and
http://www.viart.com/CMS_Layouts.html
I created a 'tiny cart' variant of this by
1. Edit templates/user/header.html file to add a tag {cart_header} at the position you want the new 'tiny cart' to appear.
2. adding the Products > Small Cart to the page, above the Global >Header block
3. Set the properties of the block as follows:
a. Tag Name: cart_header
b. HTML template: block_cart_header.html
I also edited the templates/user/block_cart_header.html to tweak its appearance.
Big downside is that to have this new cart appear on every page, you then need to repeat 2 & 3 above on EVERY page.
I also couldnt get it to sit quite right in my layout
and so I ended up removing it for now plus the hassle of repeating 2&3 on every CMS Page was a pain.
If someone comes up with a better solution, love to hear it.