public function guessConvert($value, $destinationUnit, $locale = null)
	{
		$result = array();
		if (preg_match('#([\d,\.\s]+)\s*([^\s]+)#', $value, $result) > 0) {
			
			return $this->convert(\floatval(\str_replace(array(',', ' '), array('.', ''), $result[1])), $result[2], $destinationUnit, 
				$locale);
		}
		
		return null;
	}