Yes, to remove the IR filter (from 450D, 400D) as per Gary Honis website is easy job to do.
After doing that, in order to use moded camera with my Canon 400mm f/2.8, I found out that I need some sort of IR-block filter.
The one mentioned on GH website is not good (Rocolax), it blocks too much of Halpha (at least the one I was sent), so I went to LenOpTec website (via Alibaba) and purchased excellent one (actually two samples, cut to custom size) for fraction of the price asked by Baader Planetarium.
I tested it and the results were excellent, see thread here:
http://www.iceinspace.com.au/forum/s...+filter&page=2