How can I custom message Logon ?

[quangvu30]

By default, the initiator's configuration sends the logon using Username & Password. However, I want to send a message with Account & Password. When I remove the Username field and replace it with Account in the initiator's configuration, the message sent does not include the Account. How can I fix this?

MsgLogon: 8=FIX4.4|9=0000085|35=A|49=TVKD|56=MXVMDGW|34=1|52=20241218-02:31:52.587|98=0|108=30|141=Y|554=password|10=169|

Config:
{
"application": {
"reconnectSeconds": 10,
"type": "initiator",
"name": "xxxxxxxx",
"tcp": {
"host": "xxx.xxx.xxx.xxx",
"port": xxxxx
},
"protocol": "ascii",
"dictionary": "repo44"
},
"Account": "TVKD_001",
"Password": "password",
"EncryptMethod": 0,
"ResetSeqNumFlag": true,
"HeartBtInt": 30,
"SenderCompId": "TVKD",
"TargetCompID": "MXVMDGW",
"BeginString": "FIX4.4"
}