I've heard that's one of the most difficult pieces to remove. Have you tried BPUtah.com? They sell the piece and may have instructions. Otherwise, it may be worth not breaking it to shell out the hour's worth of labor or so at your local dealer or mechanic. We had a thread about peeling silver trim, and I managed to pressure my dealer into replacing it under warranty. Good luck.
2004 Range Rover HSE
Ex-2000 Range Rover 4.6 HSE