Magento

I am trying to set up a magento multiple store mall using subdomains...The problem I am having is getting the cart to be shared between stores...when i log in to one account and switch stores it does not keep me logged in...i followed this guide on this thread on how to set it up http://www.magentocommerce.com/boards/viewthread/38627/

Anybody out there??????

very frustrated with this and need help...i followed that great guide to how to set it up but it still does not work...when looking at the posted I do not see alot of people saying that it didn’t work for them so I am mind boggled on why it doesn’t work