Where Is The Minui?

My chavrusa Yoni asked me SUCH a good question today, I thought I would share it with everyone:).

The halacha is that onee may not each the Korban Pesach unless he first "registers" called in Talmudics "מנוי". He may not just find a random group of people on Pesach night and join them in the eating of the Pesach. That being the case, how can we say in הא לחמא עניא at the beginning of maggid "כל דצריך ייתי ויפסח" - Anybody who needs should come and eat the Korban Pesach. That is AGAINST the halacha!!?? He is not registered so he may not eat.

Wonder of wonders.....