Daf Yomi - Yoma 51 - Kedusha of a Temurah

Tosfos Yeshanim (printed on 52a) brings a Gemora in Pesachim which implies that a temurah (exchange animal) from a korban Pesach is valid for the Pesach. If so, he asks, then it should be docheh Shabbos? He answers that one cannot fulfill his obligation for the korban for there is a rule stating that an obligation korban can only be brought from chulin and the temurah korban received its kedusha from the original animal. The meaning of the Gemora in Pesachim is that it must be eaten as if it would be a Pesach.

There is a famous chakirah by temurah. Where does the kedusha come from? Is it from the original korban, meaning that the owner actually transferred the kedusha from the initial korban onto the second and the Torah gave kedusha back to the first one. Or do we say that the owner accomplished nothing by making a temurah, however the Torah placed kedusha on the second one.

According to the former, it is understood why one cannot fulfill his obligation on a mandated korban for the kedusha did not come from chulin, rather it came from the first animal, however, according to the latter explanation, the kedusha did not come from the first one, rather the Torah gave it kedusha when he tried to make a temurah - if so, why can't he fulfill his mitzva of bringing a korban Pesach with the temurah?