Issue with capturing variable Parm values and placing them in Web_submit_data

I have a web page where there are different set of rows depending on what values you select on previous screens.  I am able to capture the values with the Ord=all, but how do I put the  value in the ITEMDATA section?  Can I have more rows than data in the ITEMDATA section? Your assistance is greatly appreciated.

    web_reg_save_param_ex("ParamName=chkbox",          

          "LB/IC=value=\"",         

          "RB/IC=\"  alt=",         

          "Ordinal=all",         

            LAST);

    web_submit_data("certify.do",          

        "Action=URL",          

         "Method=POST",          

         "RecContentType=text/html",          

         "Referer=URL",          

         "Snapshot=t10.inf",          

         "Mode=HTML",         

       ITEMDATA,          

        "Name=alreadySubmitted", "Value=false", ENDITEM,          "Name=signatureDateString", "Value=01/01/2015", ENDITEM,         

        "Name=select", "Value=", ENDITEM,          

        "Name=selectC152046456", "Value=C152046456", ENDITEM,          "Name=selectC152046457", "Value=C152046457", ENDITEM,         "Name=selectC152046459", "Value=C152046459", ENDITEM,          "Name=selectC152046459", "Value=C152046459", ENDITEM,         

        "Name=dispatchTo", "Value=Certify", ENDITEM,

          LAST);

ldebner