Gerard,
I don't recommend using the SqlDataSource control in the way you're describing. (I don't recommend the SqlDataSource control at all, but that's another conversation). I know that the SqlDataSource is tempting, but SQL statements should only reside in a data access component, or (ideally) in stored procedures.
If you want to use one of the supplied controls/builders to create a bridge between your web page and a result set, you might want to check out the ObjectDataSource, which (IMO) is better than the SqlDataSource. Last year I wrote a simple step-by-step guide for using the ObjectDataSource.
http://www.code-magazine.com/article.aspx?quickid=0609041&page=4Hope that helps...
Kevin
