I've used SPMetal to generate my DataContext and classes for my custom Content Types. Some of these Content Types derive from Document content type.
I need to run a Linq query against a Document Library and access the binary data for each of the files returned. The documents are returned nicely as the expected Entity types.
My problem is that I can't really figure out how to do the equivalent of SPFile.OpenBinaryStream() when all I have is a reference to my entity, without having to fetch the SPFile from the containing SPList by the document's ID first.