Problem in integrating struts 2 with struts 1

Hi,

I am having an app build on struts 1 but i want to develop other modules in app in struts2 and add to teh application. I have configured everything. But it is giving error when requesting for an action

in web.xml i configured FilterDispatcher filter and i placed struts.xml in class folder and i am trying in the following manner

<td><s:action name="HelloWorld.action">OK</s:action></td>

But it is giving the following error

SEVERE: Could not execute action: /pages/tiles/HelloWorld.action
There is no Action mapped for namespace /pages/tiles and action name HelloWorld.action. - [unknown location]

my jsp page is in pages directory of the app.

Please help me to solve this problem