Two charts in one image using pchart

Hi there

I’m trying to generate two charts into the same image. The problem arrives when I need to use two vertical axes on one of my charts. As you can see on the first chart, the right side axe is not requested by my code.

Maybe my code is bad. Maybe my approach is bad. Can you give me your feedback?

<?php   
include("../pchart/class/pData.class.php");
include("../pchart/class/pDraw.class.php");
include("../pchart/class/pImage.class.php");

$MyData = new pData(); 
$MyData->addPoints(array(-4,VOID,VOID,12,8,3),"probe1");
$MyData->addPoints(array(3,12,15,8,5,-5),"probe2");
$MyData->addPoints(array(2,7,5,18,19,22),"probe3");
$MyData->addPoints(array(14,12,10,8,9,12),"probe4");
$MyData->addPoints(array(3,4,5,7,6,4),"probe5");


$MyData->setAxisName(0,"Temperatures");
$MyData->addPoints(array("Jan","Feb","Mar","Apr","May","Jun"),"Labels");
$MyData->setSerieDescription("Labels","Months");
$MyData->setAbscissa("Labels");

$MyData->setSerieOnAxis("probe4", 1);
$MyData->setAxisPosition(1,AXIS_POSITION_RIGHT);

$MyData->setSerieDrawable (array("probe4", "probe5"), FALSE);


$myPicture = new pImage(700,400,$MyData);
$myPicture->drawRectangle(0,0,699,399,array("R"=>0,"G"=>0,"B"=>0));


$myPicture->setFontProperties(array("FontName"=>"../pchart/fonts/Forgotte.ttf","FontSize"=>11));
$myPicture->drawText(250,55,"Average temperature",array("FontSize"=>20,"Align"=>TEXT_ALIGN_BOTTOMMIDDLE));

$myPicture->setGraphArea(60,60,670,190);
$myPicture->drawFilledRectangle(60,60,670,190,array("R"=>255,"G"=>255,"B"=>255,"Surrounding"=>-200,"Alpha"=>10));
$myPicture->drawScale(array("DrawSubTicks"=>TRUE));
$myPicture->drawLineChart(array("DisplayValues"=>TRUE,"DisplayColor"=>DISPLAY_AUTO));

$MyData->setSerieDrawable (array("probe1", "probe2", "probe3"), FALSE);
$MyData->setSerieDrawable (array("probe4", "probe5"), TRUE);


$myPicture->setGraphArea(60,240,670,370);
$myPicture->drawFilledRectangle(60,240,670,370,array("R"=>255,"G"=>255,"B"=>255,"Surrounding"=>-200,"Alpha"=>10));
$myPicture->drawScale(array("DrawSubTicks"=>TRUE));
$myPicture->drawLineChart(array("DisplayValues"=>TRUE,"DisplayColor"=>DISPLAY_AUTO));


$myPicture->stroke();
?>

and my output: http://imageshack.us/photo/my-images/534/twocharts.png