Sometimes getting BizTalk to communicate successfully with Commerce Server 2007 using the provided Orders Adapter can be tricky.
Here is a quick tip when initially setting up the Orders Receive Adapter in BizTalk 2006 R2.
If you receive the following error:
Creating the search clause factory failed for Commerce Server Orders Receive Adapter. Message You are not authorized to perform the requested operation.
Make sure the user the BizTalk Host is running under is added to the Commerce Server Order Web Service using azman (I made the user an Orders Admin) and that anonymous access is disabled on the site hosting the web services.
If you are on the same domain and Windows Authentication is enabled, make sure you are not supplying a user name and password on the receive location.
Hope this helps!