Dropdown List Options Change Price/SKU/Delivery?

Hi,

I'm still getting my feet wet with eCart, and while it's all relatively straightforward, I have not come across a situation like the one we're in & wanted to ask about this:

I'm making a website for our band. We sell primarily CDs, but also downloadable sheet music and MP3s of our songs.

For each of our albums, we want to have a single product page with a pulldown in which you can select which version of the product you want to buy: Physical CD (14.95), Downloadable MP3 version (9.95), or a "instant download with purchase of the CD" for $2.00 more (i.e. for people who "still buy CDs" but don't want to wait for the package to arrive in the mail, we're happy to charge a couple bucks extra for you to have immediate access to all the tracks on the album right away.)

For accounting purposes (we have to pay royalties on our cover songs, and if we're selling someone BOTH a physical CD and an immediate download, we pay royalties twice), each "flavor" of download has a different SKU as well.

I haven't really begun playing with setting up the digital download functionality yet, but the plan at this point is to have the download triggered by the purchase of a particular SKU -- which again requires that the "add to cart" buttons accurately report that based on the option selected.

So my question is -- rather than having a separate "add to cart" button for each of these flavors -- which is clunky from a design standpoint -- how would you make a pulldown menu in which each option is not bound to a single column in the table, but rather, to multiple ones? So that if you choose the physical CD option, the cart shows a SKU of PHYS-CD (or whatever), a price of $14.95, and a description of "physical CD version", etc. but if you choose the digital download option, the cart will show a SKU of DLOAD (or whatever) and a price of $9.95? Is there perhaps also another "download" flag that needs to be set at this point as well?

I'm guessing this is just a matter of setting up separate item records in the table for each flavor of the product -- one for the "physical" version, one for the "download" version, and one for the "physical plus immediate download" version -- but then how do you alter the "add to cart" button to select one vs. the other?

I suspect I could figure out how to hack this in Javascript -- make it such that there are alternate "add to cart" buttons for each option, and have Javascript submit the appropriate fields associated with the selected option upon submission of the "add to cart" button's form -- but again, that seems like a hack. Is there a neater way to do this?

Thanks,
M2