Hey guys, thank you all for the replies.
I've found a way! My biggest difficulty was to understand the mechanism because, apparently, there are 2 different locking mechanisms as you can compare in the first 2 images, being the first one just like mine. I only noticed this after seeing lot's of different ashtrays for sale in eBay.
So my little upper plastic pin was broken, which I guess it is not to hard to happen, and I replaced it with what I had around (or, like we say in Portuguese, "desenrrasquei"). I made a small hole and put a thick copper wire that was bent in the opposite direction of the metal spring. It seems new!
The Storage bay alternative was nice, but I still prefer this way and it is cheaper.
Hope this helps someone.