We bought a mouse and a small rat put them in the same tank and let the tank sit next to the snakes tank for a week.
ive tried everything except that trick.

I will tell you though, i did try the "smaller rat" thing, and it did not work on my 970-990g mouser. I tried more than once, a small rat which is pretty much the size of a large mouse, he will show alot of interest but after a while i guess he realizes that its a rat and just retreats to his hide. I dont know if its the scent or the size of the head (a rat head is way bigger than a mouse head i noticed) that gives it away. Now with a regular rat hes gones as soon as he sees the size, and even on a ASF rat.

I have pretty much giving up, and now im just working on him eating atleast 2 mouses in one feeding as supposed to 1 mouse, since he only eats every 2-3 weeks although he is't loosing any real weight.

Thats not to say you should give up though, keep on trying, and def try that housing a rat and mouse together for a week. I would do that myself but i cannot stand having a rat and mouse just chilling in my house for that long, yuck.