How to zoom exactly to a desired scale in Flex?

Question

I am using ArcGIS API for flex 2.4 with ArcGIS server 10. I am trying to write the widget where user can define the map scale (type it in text box) and it will zoom to that scale. I successfully created a widget. But When I type scale in the text box it still zooms to the nearest LOD scale level. e.g. if i zoom to 5000 scale, it will take it as 4,514.

Could anyone suggest what change I need to make? Is there anything that needs to be defined in MapManager?

<?xml version="1.0" encoding="utf-8"?>
<!--
////////////////////////////////////////////////////////////////////////////////
//
// Copyright (c) 2010 ESRI
//
// All rights reserved under the copyright laws of the United States.
// You may freely redistribute and use this software, with or
// without modification, provided you include the original copyright
// and use restrictions.  See use restrictions in the file:
// <install location>/License.txt
//
////////////////////////////////////////////////////////////////////////////////
-->
<viewer:BaseWidget xmlns:fx="http://ns.adobe.com/mxml/2009"
                   xmlns:s="library://ns.adobe.com/flex/spark"
                   xmlns:mx="library://ns.adobe.com/flex/mx"
                   xmlns:esri="http://www.esri.com/2008/ags"
                   xmlns:viewer="com.esri.viewer.*"
                   widgetConfigLoaded="init()">
    <fx:Script>
        <![CDATA[
            //this function called when the widget's configuration is loaded
            private function init():void
            {
                if (configXML) // checking for valid content in the configuration file
                {

                }

                mapScaleObj.text = String(map.scale);           
            }

            private function doScale():void
            {
                map.scale = Number(mapScaleObj.text);
                mapScaleObj.text = String(mapScaleObj.text);
            }
        ]]>
    </fx:Script>
    <viewer:WidgetTemplate id="helloWorld"
                           width="250" height="110">
        <viewer:layout>
            <s:VerticalLayout horizontalAlign="center" verticalAlign="middle"/>
        </viewer:layout>
        <s:SkinnableContainer >
            <s:HGroup>
                <s:Label height="100%" color="#FFFFFF" fontSize="14" fontWeight="bold" text="Scale 1:"
                         verticalAlign="middle"/>
                <s:TextInput id="mapScaleObj"   text="{map.scale}"           
                             restrict="0-9"
                             enter="doScale();"
                             />
            </s:HGroup> 
        </s:SkinnableContainer>     
    </viewer:WidgetTemplate>
</viewer:BaseWidget>