Regardless of the method you use to extend purchase process objects (using an existing or new item descriptor), you may need to extend some additional areas as well:
If you extend an implementation of
CommerceItemorShippingGroup, you may need to make additional changes as described in Merging Orders in this chapter.If you add custom properties to a
CommerceItem, you may need to override portions ofCartModifierFormHandler. This form handler is capable of handling new primitive data type properties automatically. Other types of extensions require extensions to the form handler. See Handling Custom Commerce Item Properties in the Implementing Shopping Carts chapter of the ATG Commerce Guide to Setting Up a Store for more information.
