as far as i know, you should add it manually via eCart widget and upload the WA_eCart folder to update the coupon and the new setting.
this is the cons of use eCart (version 4).. i really hope the future release of eCart could handle coupon, discount, etc via database...
So far, temporary solution for me and my team is build functions that mimics eCart to rewrite some files in WA_eCart folder dynamically... its not finish but hopefully at the end of this quarter defining the coupon, discount can be done through database (so we can include it in our CMS)
hope some WA staff can give us the blueprint.. when such feature will exist
