Ecwid (the e-commerce service) doesn't support import/export of shipping rates. Find out how you can easily do this from a spreadsheet using the Selenium Firefox extension.
I provide an example spreadsheet with three UK Royal Mail tables.
MathJax looks like the way to go if you want to be able to publish mathematics easily and allow your users to do the same.
I'd recommend anyone currently using my MathPublisher plugin for Joomla to consider migrating to MathJax, especially if the limitations of mathPublisher are a concern.
I've put up a quick guide to get you started.
I am now a great fan of Concrete5, a cool CMS (content management system) that is easy for the client to use and easy and powerful for the technical team.
MathPublisher plugin - Now working on Joomla 1.6 and with simpler configuration.
Writing maths (or math as they say in the US) formulae on a web page is not the kind of thing many people will be interested in, but occasionally it can be useful. The plugin works in articles, and optionally in JComments and Kunena forum entries.
I provide competitively priced website services from complete site design, to help with specific technical aspects.
I just started offering some flexible and affordable UK based hosting packages. They use 34SP.com facilities in modern high specification world class data centers.