Just in case you haven't searched around in the SDK folder of the Commerce Server 2007 installation, there is an Adapter section which includes the following items:
A couple of notes about the message schemas. The subsystem schemas are the default, out of the box schema that comes with the base installation. If you customize any aspects of Commerce Server, you must update the corresponding schema before deploying to Biztalk. For instance, if you extended the PurchaseOrder object for Orders, you would need to use the OrderMapping.exe tool to generate the updated schema. You would need to do this for every subsystem that you customize. You can then include the updated version in the Biztalk SDK solution for deployment.
In addition to the various subsystem message schemas, the solution also includes the specific adapter message schemas, which will not change. The difference in the adapter message schemas versus the subsystem schemas is the distinction of ownership. The various subsystems own the schemas for their particular objects (e.g. Orders system and the PurchaseOrder object). For the most part, the adapter owns the error response message schemas, query message schemas, and some of the response message schemas (except for Catalog and Inventory). Some examples of these are the: OrdersQuery.xsd, OrdersAcceptBasketErrorResponse.xsd, ProfilesQuery.xsd, CatalogQuery.xsd, etc....
These message schemas are needed in order for the adapter to utilize the XMLReceive or XMLTransmit pipelines in Biztalk. By shipping in the SDK, we enable you to quickly grab the specific message schemas for quick, out of the box, deployment!
Hope this helps!