Section::setStartPosition

protected function setStartPosition($startPosition)
{
	if ($startPosition && $startPosition > 0)
	{
		$this->startPosition = intval($startPosition);
//			we can use two condition in filter on ID: in array and >=startPostion.
//			therefore prepare array of sections to export like a >=
		foreach ($this->sectionsToExport as $key => $section)
		{
			if ($key < $startPosition)
				unset($this->sectionsToExport[$key]);
		}
	}
}