mysqli vs PDO Webservice Return Values

I have a dynamic werbservice that I was unable to find a way to bind the variables to in mysqli, the default for Flex webservices, but was able to find a nice solution using PDO. The problem I have run into is that PDO does not seem to have a bind_result function like mysqli. So the problem is that I am unable to find a clean way to return my results in a way that I can set my return values for the webservice in Flex. It is just returning an object. So in PDO, I am doing this:

    $result = $stmt->fetchAll(PDO::FETCH_OBJ);  // I have tried FETCH_ASSOC also

    return $result;

In mysqli, this is what is typically done:

    while (mysqli_stmt_fetch($stmt)) {
      $rows[] = $row;
      $row = new stdClass();
      mysqli_stmt_bind_result($stmt, $row->uniqueID, $row->latitude, $row->longitude);
    }

When I do a var_dump of the PDO $result, I get the following:

array(25) {
  [0]=>
   object(stdClass)#3 (3) {
   ["uniqueID"]=>
   int(12335513)
   ["latitude"]=>
   float(39.6586675)
   ["longitude"]=>
   float(-86.0648281)
  }
  [1]=>
  object(stdClass)#4 (3) {
   ["uniqueID"]=>
   int(12368285)
   ["latitude"]=>
   float(39.6176244)
   ["longitude"]=>
   float(-86.8947852)
  }

When I do a var_dump of mysqli $rows, I get the following:

array(25) {
  [0]=>
  object(stdClass)#3 (3) {
   ["uniqueID"]=>
   int(12335513)
   ["latitude"]=>
   float(39.6586675)
   ["longitude"]=>
   float(-86.0648281)
  }
  [1]=>
  object(stdClass)#4 (3) {
   ["uniqueID"]=>
   int(12368285)
   ["latitude"]=>
   float(39.6176244)
   ["longitude"]=>
   float(-86.8947852)
  }

They look exactly the same to me, but when I set up my services with mysqli, I am able to set the return type for all the variables in the array, and in PDO, Flex only sees an object returned. I want it to come back as an arraycollection. Is there a way I should return the data in PDO so that I am able to send back an array with datatypes instead of an object? Any ideas?