Ship-to Location driven tax rate derivation setup in an instance upgraded from Rel11.5 to Rel12.1.x

Hi fellow EBS Financial implementers,

Has anyone configured eBTAX post upgrade from Rel11.5 to Rel12.1.x to derive and calculate tax based on (1) Ship-to Location and (2) GL Natural Account?   I've configured ebtax before but only in fresh Rel12 installs.

I have all my configurations in place but the tax is not firing off.  I later learned that in an upgraded instance several more steps are required, like direct tax rate determination rules.

Can someone please provide me with documentation or reference sources detailing the next steps I am still missing to do, like these extra tax rules (determining factor sets, etc), tax classification codes, application tax options hiearachy, etc.