I'll be very interested in the outcome of this. I'm seriously considering the Chamonix 45N and one of my requirements is shooting with Efke IR820. Google found a photographer on Flickr with several Efke IR images made with a Chamonix 45N, such as this one, so at least one person has used this combination successfully:

http://www.flickr.com/photos/9785954@N05/2741701515/