(1) I have updated your current StrikeIron Basic Provider to be v5 as v4 is obsolete and no longer available.
(2) The ability to use the Provider in calculating taxes is dead. It happened in v4 and is still there in v5. The provider works as it is supposed to do within the admin page but will not run a gettax during check out. I see that the code has changed to add a TaxClassID. What is that and how do I set it? I need a fix right away.
(3) Also I have modified the code for the site to support products by CustomerID and am in the process of modifying it to support MultiStore Sites on the Same Database.
Oh and by the way it hasn't worked since v4 either ....