Call Denon America and see(pray) if they have them in stock. I have a highly modified Marantz and had the same concerns. I called Marantz America and found that they still had them in stock for around $90. I bought one even though I don't need one right now. I figured for $90, it's peace of mind to have one around.
I don't know that I could install it myself, but at least I know that I have the necessary part. I can always find a tech if I can't install it.