[flexcoders] "Infinity" value in Datagrid

[shrike6_7]

Hi, I have a Datagrid with dataProvider="{productList}", productList
is an ArrayCollection, when I get the records from the server in XML
format I have a string 8e4376, but the DataGrid show me 'Infinity'. 
How can I tell to the grid that 8e4376 is a string?

this is the code of the httpservice:

public var gateway_object:HTTPService = new HTTPService();
gateway_object.url = URL_XYZ;
gateway_object.method = "POST";
gateway_object.resultFormat = "object";

var resultObj:Object = event.result;
productList = resultObj.list.product;

Thanks