Yes Satela you are correct about that. Blancowl I will only tell what I can, I don't like discussing this on forums. It seems to me you are trying to summon a Lwa that you clearly know nothing about, Papa Legba or Eshu is always invoked at the start and end of every ceremony, or ritual. Before speaking to any other Lwa , you must consult with Legba, he will determine who passes between those gates, why? because he stands at each crossroad.
I will not give out anymore information, anyone else that has been wondering this I suggest you start digging up some information about him.
As always I wish you all the best :D