Weird Shipping Question for combination download and Physical Products

Hi,

So I have a music store set up and am selling both downloads (tracks and full albums) as well as physical CD's... sometimes I want to sell both together as a combination. I handle all pricing and options through attributes and everything works perfectly until it comes to checkout...

I need to find a way to make it so that the shipping option is skipped when they choose the downloadable only attributes and that when they choose the physical attributes the shipping module is engaged... and when there is a combo product (i.e. phsiycal CD with download) that shipping is also engaged... remember these attributes are all on the same product.

Here is an example:

1. Purchase Complete MP3 Album 9.99 (download product shipping not required)
2. Purchase Physical CD 14.99 (physical product shipping required)
3. Purchase Physical CD + Instant MP3 Download 15.99 (Physical and Downloadrequired)
4. Track 1 0.99 (download product shipping not required)
5. Track 2 0.99 (download product shipping not required)

If I select product is virtual when setting it up then it will no longer give me the option to collect shipping info for the physical product attribute... so I chose the combination product... but that doesn't seem to work... Im not sure if this is too confusing... Can anyone offer some suggestions on how I can make this happen? Or some sort of hack that would achieve the same result?

I thought about the idea of somehow making any attribute which has a weight of 0 be free shipping and if there is a weight then the shipping is engaged.. I think there is a way to do this.. but perhaps there is a smarter way.

Thanks for your help.

See if this FAQ helps you to setup the Products that are Downloads/Combos ...
http://www.zen-cart.com/content.php?297-can-i-have-products-be-both-physical-shippable-and-virtual-downloadable