I am working with Recurring Profiles and I'm trying to understand why the promotion "shopping cart price rules" don't apply for these items? Thanks
"Nominal items are not added to regular totals (taxes, subtotal, and grand total)." (source)
Discounts occur through totals models which are not involved with the calculation of nominal products. Why this is the case? Probably to either ship the feature on time or to reduce complexity, given that there are already three separate totals models involved in the calculation of nominal products.
Refer this. It has more info about nominal products and their behaviour. http://www.magentocommerce.com/knowledge-base/entry/working-with-recurring-profiles/