no sales tax calculated for anonymous users

hello and thanks-

i am using drupal 4.6.6 with pretty much all the latest versions of the ecommerce modules from cvs for the 4.6.0 branch.

and i have had ecommerce working perfectly since february for anonymous users.

in fact, i didn't even know that ecommerce apparently WASN'T working that well for anonymous users-
for some people-

without the various patches, etc.- that i have since read about-

because the various modules of address.module, cart.module, store.module, etc.-
worked right from the start for me with no patches needed.

or so i thought.

because just now i went to make a shop that needs sales tax calculated.

so now what happens is, anonymous customers can still breeze right through checkout and go all the way to paypal-

for both shippable and non-shippable products-

and checkout and everything works 100% fine and great-
but with one major problem:

sales tax is NOT calculated for anonymous customers (tax = $0.00)-

BUT-

sales tax IS calculated and working perfectly for logged in and authenticated users.

any help on this would be greatly appreciated-

i saw something somewhere where someone posted that maybe checkout is not parsing the address values properly for anonymous customers-

and i am wondering is this something that i should look to try to fix in address.module or tax.module or cart.module or store.module ...?

please advise and thanks...
really want to use the ability for people to complete a purchase without having to register as a user-

its so quick and easy and works great right now-

but i really need the sales tax to be calculated for anonymous users as well as authenticated users.