Simple enough.
You use a chat packet to do the popups. Not a 1052 packet.
Dialog = 2100,
LoginInformation = 2101,
The login information one is used to either trigger the final login stage (ANSWER_OK) or trigger character creation (NEW_ROLE)
I assume you mean the auth response packet though seeing as you're mentioning a key (1052 is Client>Server... not server>Client)
Auth response (in new versions anyways) is 1055.
The "LoginFlag" as you call it I assume is what I refer to as the key. 2 = valid login, 57 = banned, 1 = invalid user/pass I think in new versions.
IE:
Code:
Client.Send(Packets.AuthResponse(Program.GameIp, Client.UID, 2, Program.GamePort));
//that would be a valid login
Code:
Client.Send(Packets.AuthResponse("0", 0, 1, 0));
//That would be invalid login (invalid user/pass