Product alias duplicated, not friendly URL

[El_Loboo]

Hi,

I have an e-commerce website www.juguetitossex.es

Sometimes the product name repeats and the URL of the last product with the same product name is not good, some like this: http://www.juguetitossex.es/lenceria/body-con-pedrerias-2013-08-09-09-57-281564578252-detail

I would like delete date and rest of the numbers (I know product alias must be unique). I would like know which file generates product alias for reprogramming and it shows something like this:

http://www.juguetitossex.es/lenceria/body-con-pedrerias-2-detail

If I insert a new product with the same product name:

http://www.juguetitossex.es/lenceria/body-con-pedrerias-3-detail

It would be easy but I don't know which file generates product alias.

Regards.