Hi leon,
Is this what you mean?
http://www.sciencecenter.net/hutech/haimage.htm
I'm interested too as we seem to fit all the criteria...we both have spectrum-enhanced(modded) DSLRs and IDAS LPS filters.
From the article seems all you might need is the Kenko R1(R60) filter and they're pretty cheap!
What do you think?
Doug