Using SqlClient linq functions?

Has anyone had any luck getting the Sql functions for linq (referenced here: http://msdn.microsoft.com/en-us/library/bb399263.aspx ) to work?

There's supposed to be a SoundEx function for Linq to Entities in there, but for the life of me, I开发者_如何学JAVA can't seem to get any of the functions listed in that page to show up in Visual Studio. It's probably because I am missing a reference, or a using statement (or both), but I'm at a loss. Anyone out there used these?