I'm having this issue too. Did you ever resolve this? I'm using Google Earth version 7.0.3.8542
A line with the style bellow should 4 pixels wide, 1 blue pixel to each side and 2 yellow pixels down the middle. Instead it is all yellow.
<?xml version="1.0" encoding="UTF-8"?>
<Document>
<name>gx:AnimatedUpdate example test 7 fast two lines</name>
<open>1</open>
<Placemark id="STJ_line">
<name>STJ_line</name>
<styleUrl>#Yellow</styleUrl>
<Snippet></Snippet>
<MultiGeometry>
<LineString>
<tessellate>1</tessellate>
<extrude>0</extrude>
<altitudeMode>clampToGround</altitudeMode>
<coordinates> -64.716828,18.317366,0.000000 -64.721526,18.319714,0.000000</coordinates>
</LineString>
</MultiGeometry>
</Placemark>
<Style id="Yellow">
<LineStyle>
<color>ff00FFff</color>
<width>4.000000</width>
<gx:outerColor>ffff0000</gx:outerColor>
<gx:outerWidth>0.5</gx:outerWidth>
</LineStyle>
</Style>
I also tried using <physicalWidth> tag instead of <width>, but then my line was always 1 pixel, regardless of zoom level, even when the physical Width should have been 200 meters.
Cedric