Hello CraigR, thanks for confirm a possible solution. I already thing that kind of solution, i even already "built" the eCart Interface so my client would able define almost everything we can set in the toolbar (decimal separator, the currency, etc).
it's not finish yet as i'm in process to write one by one of every possible code that eCart write in the .php cart specification... but i'm using eCart 4.. kind a wish eCart 5 would able to do the job for me (especially the discount feature) to save my time (it's a worth reason for an upgrade).
how long you build the 'extra' code for eCart ?