The answer depends on the nature of your 'linked promotions'. It might be that you should add an entity reference field to your line item type, then add the field to the shopping cart view. If your promotions are based on tagging products with taxonomy terms, it's as simple as adding the field to the cart view.

Or, as @Strae said, you could alter the line item's title via hook_commerce_cart_product_add. Yet another way would be to alter the line item's 'label' via Rules and show that in the cart instead.

Change Drupal Commerce line item titles
I would like to embed some C# .Net code that does some simple Encryption/Decryption functions into a web page. This will be an internal web page so users will be implicitly trusted. Is there any way to do this? I will need to hit user's Windows-MY key store (via CAPI) to pull out the keys for decryption and hit an LDAP server to grab public keys for encryption.
