Can MarketPress plugin works with Templatic e-Commerce Theme?

Hi,

I've recently set up an e-store using Templatic e-commerce theme.

However, I'd need multiple shipping options ie. Free, Local, Registered, Overseas etc. at point of checkout which the theme does not support.

Understand MarketPress have some shipping options which I can try out.

Question is, the Templatic theme comes with the e-commerce plugins/features in-built, will adding additional plugin like the MarketPress override the feature ... or rather, how can the checkout page know and add this extra shipping fees?

I need help from you guys and I've tried using WP E-Commerce Extra Shipping Options plugin but it doesn't seem to work with the template.

Thanks and best regards, William