Let me see if I get it...
In a .05/.1 game, someone raise to .4, and you are holding a low pair. If the villain had at least .4*12 = $4.8 and you too, then the right move is call if not, then fold. (I took the 12 from the 12:1 that you spoke).
If this is correct, then you need win in average 70,8% of villain's whole stack (asuming he had $4.8) in the hands that you hit your set.
Sounds pretty difficult to me reach those numbers, because many times you hit your set but the villain had a better hand, or the board is so scary that you are afraid to bet in big.
And in addition we are forgeting the money that you lost preflop when you call a .4 bet, but another player after you make another raise and you are forced to fold.
I still want to see a link or a reference or something with a good explanation about this point. If anybody have a good site to give me like a reference of this subject or can post a good example with numbers justifing that make this call is the right move I will be eternally greatful.