Hi jObE,
Here's a short summary of the conflict between STL and CTE in zc1.3.8:
Normally, when calculating taxes, there are two core tax functions used: zen_get_tax_rate and zen_get_tax_description. When STL is turned on, a third core tax function called zen_get_multiple_tax_rates is used instead of the first two.
The root of the conflict is that CTE makes changes to only the first two of these three core tax functions. The third one (zen_get_multiple_tax_rates) is new to zc1.3.8 and must have slipped under the radar when CTE was updated to support zc1.3.8. I'm hoping that numinix (of customer tax exempt fame) will soon make the necessary changes to CTE so that it plays nicely with STL and any other code that uses zen_get_multiple_tax_rates in the future.
It's a shame that you feel you can't use the latest version of zencart because of this issue. The hints above should give you a good idea where to start if you want to try to fix it yourself while we wait for the necessary changes to be made. It shouldn't be very difficult but I'm afraid I don't have time right now to dig around in numinix's code.
You'll have to set your taxes up normally, SplitTaxLines only splits them out into separate lines.
Here is a good guide:
http://www.zen-cart.com/forum/showthread.php?t=35032
It looks complicated but it's not really that bad once you get into it. Note that the section labelled 'PROBLEMS' is no longer a problem if you are using the SplitTaxLines mod. That's why I created it in the first place!
Good luck, keep us posted on your progress!
Alan




