I have answered you in the support ticket you submitted. I will post it here as well:
There are no separate SKUs for variation combinations. Each variation has a place to enter a SKU and these get appended to the product SKU. So if you have T-shirts and the SKU is TSHT005, and a red variation that has a SKU of 003 and a small variation with a SKU of SM, that t-shirt would have a SKU of TSHT005|003|SM.
Currently, the eCommerce module does not support product variation dependencies. I have spoken to the eCommerce team and this is high on their priority list and will be in a future release. There is a logged feature request for this in PITS where you can vote to increase it's priority.
Two possible workarounds:
1. Create a single variation that includes only the valid variations - Red_Small, Red_Med, Blue_Large, etc.
2. Use the new Pre-Processing hook as shown here. Here you could write code to check for valid combinations and reject invalid ones as out of stock.
I am glad to see we have a bit more chatter about this topic. I have yet to fully dive into this portion of the project that I spoke about originally and am still holdin out for a solution in the coming updates. I have been mainly focusing on a robust tag system in the backend for all products, in hopes that I can manipulate those tags on product display through backend code. I will keep everyone updated if I find a good solution to the attribute issue with each variation.
Keep truckin forward guys!
Ecommerce in 6.0 has made many advances including workflow, multi-site, better out of the box shipping providers, etc. However the attributes remained the same for now. You can have multiple attributes with mutiple values per product but there is still no inventory or sku system for managing the different between shirt > large > red and shirt > small > black.
We are working constantly to improve the system so thank you for voting on this feature.