I have done something similar to this.
Enter Storm Peaks and say "Vyragosa tagged and killed at [insert Random time] by me. Estimate spawn time will be in about 4 hours. Just letting you know."
I had Skinning at that time so i told them that i skinned corpse that is why it disappeared.
Kinda a A-hole move to make but i spent over a year camping it and i wouldnt let some newbie take my glory (^^_)