Microsoft have released a tool for developing BDC XML Schems catalogs and it’s part of the Microsoft Office SharePoint Server August SDK.
Here is the download link: http://www.microsoft.com/downloads/details.aspx?familyid=6d94e307-67d9-41ac-b2d6-0074d6286fa9&displaylang=en
To know more about BDC tool read here: http://blogs.msdn.com/sharepoint/archive/2007/08/22/announcing-the-microsoft-business-data-catalog-definition-editor-for-microsoft-office-sharepoint-server-2007.aspx
Note: it works with AdventureWorksDW not with AdventureWorks
