How do you do an outer join with DataTables in .NET 2.0 ?

Last week, I had to join two DataTables together using an outer join.  Seems easy right?  And if you're thinking, PIECE OF CAKE!!!!!!!!!!!!  Just requery the DB.  Or mabye you're thinking to yourself, just use LINQ.  HHHHHMMMMM I would LOVE to use those things but the problem is I'm tied to .NET 2.0 and unfortunately the data is already in an XML file and I'm not able to requery the db again.