Thank you everybody for your answer, I'll manage to put a router adn do as victor says.

I don't have a router in that network(yes it's something a bit special and isolated) so I need that 1 of the AP work as DHCP server to give IP to the LAN interfaces. I was thinking the same you tell...

Model : Hardware Version : Not Clear Firmware Version : ISP : I need to connect 2 TL-WA7510N, with a distance of 500m, but it won't use internet or router. Its used only to connect 2 LAN interface....