The atg.adapter.gsa.GSARepository class includes these two properties:
dynamicTypesEnabled– iftrue, enables creation of dynamic subtypesdynamicPropertiesEnabled– iftrue, enables creation of dynamic properties
These properties are false by default. To enable support in a specific repository, set these properties to true on the repository component.
For the product catalog repository (/atg/commerce/catalog/ProductCatalog) and the content management repository (/atg/content/ContentManagementRepository), Core Commerce sets these properties to true:
dynamicPropertiesEnabled=true
dynamicTypesEnabled=true
Note that even if dynamicTypesEnabled is true for a specific repository, you can create dynamic subtypes only for item descriptors that define a subtype property. For example, the definition of the sku item type in the product catalog includes the following:
<item-descriptor name="sku" sub-type-property="type" ...>
See the Item Descriptor Inheritance section of the Repository Guide for more information about creating item subtypes.

