Do you have any other bears coming in? If so, limit the amount of food you put out to creat increased competition for the grub...less food means they have to come in earlier to get some food.........it's like a buffet....If there is limited food, the buffsters will be coming in early to get their food.
One other thing that you can try to make it appear that there is other bears in on your bait is to introduce other bears scat which will increase competition as the existing bear thinks that there is others dining at the table along with him.....important to limit food as well, or to actually remove the bait after you make the noise that you were there. When the big fella comes in, smells the other bear scat and sees that the barrel is empty, well......he knows the next time he better get there a little bit earlier to be able to enjoy some grub.
Seems like a bit of work, but it does work and if you sit and think about it, it makes sense. Good luck with the big one and looking forward to seeing some pics in the day light with smile on your face
Marco