I've created a form (don't mind the errors on the page), which loads a set of names, and prices, dynamically. Everything is shown perfectly.
http://dnp.yume.nl/abonnementen/
when clicking some of the options, the total field updates perfectly. Then, when checking out, i notice that these objects aren't taken into account, and my bank doesn't see them. They are not added to the final price.
To test, i've split my form in two pages. First page the dynamically added options plus a total field, second page just a total field. On the first page, total field is nicely updated. Then i click next, and the total field says 0.
I've also added a product with an option field above, and just populated that one in the form, and that one is doing perfectly fine!
