I think it would be a great change if the editaddressST/BT to was changed just a little.
Currently. If a user has input a shipto address it shows in the bottom in <li> format. When clicked refreshed the page with that information loaded and then they have to save again to return to cart. This could be done simpler.
Load the address fields into div(s) with a check box or radio button and a save/cancel button. If the users selects a different address, via the check box or radio button, it returns to the cart.
If they wish to edit the address then there should be a link by the "Delete address" that says "Edit" and when they do that it loads the information back in the form for them to edit and save. That is my observation of what the name brand stores do. Seems simpler and easier to the buyer.
[attachment cleanup by admin]
Nice idea, make a patch :-) http://dev.virtuemart.net/projects/virtuemart/wiki/Setting_up_a_Development_Environment
Lol I can try. I am unsure my skills are good enough.