Scatter chart always connects markers with lines (like lineMarker)

[githack]

Running the 33chartcreate-scatter.php example with PHPExcel_Chart_DataSeries::STYLE_MARKER instead of STYLE_LINEMARKER, Excel and OOcalc still connect the markers with lines.

This issue has also been mentioned here.
http://phpexcel.codeplex.com/discussions/445396
http://stackoverflow.com/questions/16977354/set-scatter-chart-type-in-phpexcel
http://phpexcel.codeplex.com/discussions/444551

Saving the file as Excel2007 from OOCalc, results in a chart1.xml that includes the following lines in the <c:ser>.

<a:ln w="28440">                                            
<a:solidFill>                                               
<a:srgbClr val="be4b48"/>                                   
</a:solidFill>                                              
<a:round/>                                                  
</a:ln>

When the chart sub-type is manually fixed (in OOcalc) to not have connecting lines, the resulting chart1.xml still has <c:scatterStyle val="lineMarker"/> . A scatter chart generated by OOCalc also has <c:scatterStyle val="lineMarker"/>.

From the Excel2007 XML spec...

One of the posters linked above mentions a work-around of making each point it's own series, but if someone has a better understanding of how Excel (and OOCalc) interpret the chart style, perhaps there's a way to make this work the same way that Excel and OOCalc do it.