Have looked at this prior to posting…
The issue is not to do with the large message handling within biztalk, but the fact that the sql adapter pushes xml data to sql using a string attribute. The string ends up at around 50mb which causes the adapter to throw the outofmemoryexception message. At this point I guess the entire streaming model of bts breaks down and we are dealing with large memory consumption. Anyway I think I have cludged my way around it!