I remember reading something about it on the The End forum, but I can't remember what the posts said, and I can't find the topic now.
Oh, and the acoustic riff that comes at around 1 minute in Ulver's Bergatt - Inn i Fjeldkammaren sounds exactly like the acoustic riff in The Funeral Portrait. EXACTLY. Then again, I think Mike has admitted he borrows stuff like that all the time, we just don't hear the songs he borrows from that often.