We recently made the update where we can populate a required custom field in Rally with a default value to facilitate the integration with required custom fields. This idea is to take it a step further and provide custom field integration mapping between Aha! custom fields and Rally custom field that would support bi-directional integration/updates.
We have launched an enhanced Rally integration. This integration will allow you to create 2-way custom field mappings, along with several other new capabilities including the ability to: