Help needed with client.

Hi guys, can someone please help me with this.
I have start to make own sioc to 777 overhead.
I have overhead buttons on mastercard and i need to send also commands to client computer, where i have MFD program. So, i have make sioc and using FSuipc Joystick64 to send commands. problem is what i exactly need to write to client ini ? Lets say that i need to send info of left bus tie ON. So, key to that is S and joystick64 bit is 12. No problem with sioc or Fsuipc, only with client.
Thanks
Marco