Adding products to cart with additional properties

I don't really know how to "name" this problem, so I'll just try and explain really well.

The site we're building sells tshirts, and when users pick a design they can customize their shirt for style, color and size. When they add this to the cart, everything is fine. BUT, if the user goes back to the same shirt design and tries to add it again using a different style, color or size, ecart simply tacks on to the quantity of the existing item in the cart without using the new settings. Using ecart 4.5.0. on PHP server.

What I NEED it to do is create a new entry in the shopping cart for each product added, although IDEALLY it would be great if the site compared the properties of each and only created a new entry if the properties were different.

See the link below if you want to use the site and test this out yourself.

P.S. note that there are bugs, incorrect links and unfinished pages on the site right now, obviously since this is not a live site.

P.S.S. some of the pages on this site contain offensive language. FYI.

*LINK REMOVED*

Any help with this is VERY much appreciated, as we cannot launch the site without fixing this problem. These products all have different prices, and users could exploit this to buy stuff at incorrect (see cheaper) prices.

I think i had this same problem.
In your ecart object, did you make each column unique (style,color & size)?

Yes. All three props are in there as productstyle, productcolor and productsize.

ok, but did you check the checkbox 'unique' after name and output type under tab columns of the eCart object?

Sure didn't. Seems to work perfectly now, thanks a ton.