getDataProperty for empty xml data cells return "0'

when I retrieve some info using the following statement:
var cellValue = this.getDataProperty("value", rowIndex, 1); 
  I get "0" when the xml element is empty.
This is due to the conversion done in the following line

obj.getValue = function( i, j ){
...
    var value = Number(text.replace(/[,%\$]/gi, "").replace(/\((.*)\)/, "-$1"));
    return isNaN(value) ? text.toLowerCase() + " " : value
}
  Is this a bug?

Also, the text.toLowerCase() is poblematic.

Ok... I give up and use

getDataProperty([b]"text"[/b] rowIndex, 1); 
  This works better.