Unable to Use My Custom TextProvider from Action getText() methos

I build my own Text Provider with

public class MyTextProvider extends TextProviderSupport ...

and configure in struts.xml

<bean class="lt.web.core.MyTextProvider" name="myTextProvider" type="com.opensymphony.xwork2.TextProvider" />
<constant name="struts.xworkTextProvider" value="myTextProvider" />
<constant name="system" value="myTextProvider" />

But when i make inside and action.. this.getText("whatever"); in does not run my custom provider..