OK, I see. This is a bug that i have logged, it should be corrected shortly, it should allow for the use of your own table instead of forcing one of the presets. I will let you know an update is availbale to correct this.
as for the styling, the checkout wizard has options to use an un-styled form on the last tab. if you want to remove the styling completely, you can remove the the CSS reference page or delete the css file.
you can also use form builder to create your own form styles to match the site, save the form design as a preset and select that for use in the checkout wizard.
also, the display manager allows for creating custom designs to match your site and use later.
