Hi, we were able to find the right structure for KML. Here is the one-

FSL__Polygon__c myPolygon = new FSL__Polygon__c(
                Name = 'Central SSS1'
                ,FSL__Color__c = '#5679C0'
                ,FSL__KML__c =  '<?xml version="1.0" encoding="UTF-8"?> '+
                '<kml xmlns="http://www.opengis.net/kml/2.2">'+
                '<Style id="CentralSSSStyle">'+
                '<LineStyle>'+
                '<width>1</width>'+
                '</LineStyle>'+
                '<PolyStyle>'+
                '<color>80C07956</color>'+
                '</PolyStyle>'+
                '</Style>'+
                '<Placemark>'+
                '<name>CentralSSS</name>'+
                '<styleUrl>#CentralSSSStyle</styleUrl>'+
                '<Polygon>'+
                '<outerBoundaryIs>'+
                '<LinearRing>\n'+
                '<coordinates>-89.02172505348693,47.81952924639332,0\n'+
                '-84.18774067848693,48.01097620848099,0\n'+
                '-84.89086567848693,46.22441984873406,0\n'+
                '-88.34057270973693,45.91190522847453,0\n'+
                '-88.90087544411193,47.53103006689299,0\n'+
                '-89.30736958473693,47.77524856801052,0\n'+
                '-89.02172505348693,47.81952924639332,0\n'+
                '</coordinates>\n'+
                '</LinearRing>'+
                '</outerBoundaryIs>'+
                '</Polygon>'+
                '</Placemark>'+
                '</kml>'
                ,FSL__Ma_La__c = 48.01097620848099
                ,FSL__Ma_Lo__c = -84.18774067848693
                ,FSL__Mi_La__c = 45.91190522847453
                ,FSL__Mi_Lo__c = -89.30736958473693
        );
        insert myPolygon;