Add to cart from outside zen

Hi, I have jsut installed, done some reading and playing and have one or 2 questions.

The massive one for me is this:
How/Can I create an add to cart link that does not reside in zen cart. So for example if it was an external catalogue. Or, if I write my own catalog that pulls the data in from the zen table. Is this possible? And how?

From what I've seen each product has its own form that gets submitted with a zenid. The zenid concerns me and the rest seems doable.

Is there a fully blank template for the shopping cart and checkout?

I am sorry for questions which may or may not have been answered before but I couldnt find anything in these specific areas.

Seems a very nice and active community, I look forward to getting involved.

Why would you want to duplicate a catalog outside of Zen Cart?

Kim:

Why would you want to duplicate a catalog outside of Zen Cart?

Edit: Actually the question should be: Why would you want to duplicate a catalogue inside Zen Cart?

Because most of the people I deal with already have a catalogue and want to add the ability to add these to a shopping cart. Its called using a legacy system and integrating with it. It is the prerequisite by which I score every shopping cart application I review. After all, is a shopping cart a catalogue? No.

I did find that you can add a product with no issues. I have not gone through the whole process as yet thats the final piece of the puzzle where most apps fall over. A shopping cart that is tied to a catalogue is a badly designed cart. Bold statement I know but true none the less.