用于创建自定义SQL Server“数据源”数据提供程序的文档

I'd like to write an import driver that will allow my proprietary file type to show up in the import wizard "Data Source" dropdown for SQL Server 2005 (or any version of SQL Server, for that matter). I see other vendors who've added their formats to this list - is there documentation for how I would put a driver together? I've searched MSDN and Google and I can't seem to turn up any leads, though it's clearly out there somewhere. Thanks!I'd like to write an import driver that will al