I did some searching and see that ExecuteJoinedDataSet will not work with the Where clause in 2.1. If I want to query a table with WHERE, but want the FK objects values to be bindable is the easiest way to just create a custom class(my table has tons of FK references).
Could you give us an example of what kind of query you are trying to write? If you are just trying to return a DataTable without creating a custom class just write your query and use the ExecuteReader which Returns an IDataReader. The IDataReader is bindable and if you need more you can just load it into a DataTable.