sure, the nickname is contained just in the first connection packet:
Code:
        b = 0;
        b = write_bits(-1,      32, buff, b);
        b = write_bits(0x6b,    8,  buff, b);
        b = write_bits(proto,   32, buff, b);       // protocol
        b = write_bits(3,       32, buff, b);
        b = write_bits(chall,   32, buff, b);       // challenge
        b = write_bstr(buff, b, nickname, -1);      // nickname
        b = write_bstr(buff, b, "", -1);            // certificate?
        ...