Have these, maybe help.
0x28d
struct PACKET_CH_REQ_IS_VALID_CHARNAME {/* this+0x0 */ short PacketType/* this+0x2 */ unsigned long dwAID/* this+0x6 */ unsigned long dwGID/* this+0xa */ char szCharName[24]}
0x28e
struct PACKET_HC_ACK_IS_VALID_CHARNAME {/* this+0x0 */ short PacketType/* this+0x2 */ short sResult}
0x28f
struct PACKET_CH_REQ_CHANGE_CHARNAME {/* this+0x0 */ short PacketType/* this+0x2 */ unsigned long dwGID}
0x290
struct PACKET_HC_ACK_CHANGE_CHARNAME {/* this+0x0 */ short PacketType/* this+0x2 */ short sResult}