MarketPress: Sidebar Categories

Okay I'm having a problem with this MarketPress. It seems that the sidebar widget for category display doesn't work like 99.9% of the other e-commerce solutions on the market. I need a sidebar widget that displays the main categories on the home page only. Then when a main category is selected and opens then the sub-categories are displayed in the sidebar. How come this was never included in an e-commerce package and how can this be setup? I have installed widget after widget and none of them seem to work because my Product categories won't display their ID's even with a force id script. Do they even have ids? Is their even a widget that works with this MarketPress to do what I need it to do which is basically operate like a NORMAL e-commerce site.