Working with Checkboxes in Loadrunner (Web HTTP/HTML)?

I am trying to record a simple Web Application which as activity of checking checkboxes as below and clicking on Submit button:

After recording the script is generated a post request as below:

web_submit_data("NonInvObjectSubmit", 
    "Action=URL", 
    "Method=POST", 
    "RecContentType=text/html", 
    "Referer=URL", 
    "Snapshot=t23.inf", 
    "Mode=HTML", 
    ITEMDATA, 
    "Name=PageStart", "Value=1", ENDITEM, 
    "Name=[4].bCheckBox", "Value=true", ENDITEM, 
    "Name=[4].Id", "Value=11701", ENDITEM, 
    "Name=[4].bCheckBox", "Value=false", ENDITEM, 
    LAST);

Observed the Value = 11701 is incrementing for each time the checkbox is used.
Replaying the same with different Index number, doesn't actually checks the checkbox.(tried providing empty Value, Random Value but nothing worked.)

Please Help. Thank you