Hi Trevor,
I recently shot IC2118 with a Canon 450D and you'll need a lot of exposure. I took 7 X 10 min subs @ ISO 1600 at F4.5 and at a dark sky location. It was still pretty dim before processing. So 5 min subs @ISO 800 and F5.6 is asking a lot. Certainly take the polariser filter off and try 1600ISO and 600sec subs. Link here to my attempt -
http://www.iceinspace.com.au/forum/s...ad.php?t=40414
Craig