Shopping cart empty when logging in account first

We are having a problem with our shopping cart showing as empty when our customer logs into their account before they start shopping.

When our customer clicks on My My Account link (http://www.highgravitybrew.com/ProductCart/pc/custpref.asp) It redirects to the following link so they can log in: https://www.highgravitybrew.com/productcart/pc/Checkout.asp?cmode=1

Once they log in the link changes to https://www.highgravitybrew.com/productcart/pc/CustPref.asp.  From here when they start shopping it takes them to our home page which doesn't have the https prefix.  They then start adding items to their shopping cart but then when they go to checkout, the shopping cart is empty.

Redirecting to the home page is opening a different session.  I confirmed this because I have have a custom pricing category that doesn't show the price difference after logging in and browsing the store unless I use the https prefix.

All links are exactly the same except for the http vs https prefix.  They are all using www.highgravitybrew.com.  We are also using Keyword-rich URLs.

If a customer doesn't log in until they checkout the shopping cart is fine.

Has anyone else seen this before? It is driving me nuts.

Ah the joys of Go Daddy - or should that be Go Crazy :-)

Anyways, a dime to a dollar the problem is IIS7 “New ID On Secure Connection (keepSessionIdSecure)”   http://wiki.earlyimpact.com/developers/timeout-issues#iis7
If, as I suspect from your SSL cert, you are hosted with GD then don't be put off if the first person you speak to on their support desk is unable or unwilling to help. Try again until  someone says OK and sorts it out for you.