Hello, I am trying to access from Rules the custom fields of my product at the stage of the checkout status of an order, but I am having a hard time doing so.

I have been able to access the custom product fields on the generic event of calculating the product price and using a Rule component, but in this case that approach does not seem to work because it looks like the checkout event is not providing the appropriate variables.

I am debugging the line items at this point from Rules and see that, among other things, the commerce_product element of the line item is "und".

Any help greatly appreciated, thanks.