did you contact SP asking of they have any of those keys? Often times you can buy left overs, and I imagine there are a TON of leftovers from R4. I recently completed the majority of a blue on white Raindrop Tsangan kit from the left overs. It can get expensive at $2.50 a key but if you only need a couple then it is worth it, I wouldn't want to buy a full 104 set as leftovers though.