AddThis

Problem in Re-Assiging values in addthis.button("#btn1",.......

Hello every one,

I am facing very difficult problem , i am not getting what to do plz help me.
I am assigning configuration to my addthis button in Javascript and but works first time only means suppose i am assigning this button for link say "A" afterwards using javascript i am assigning link "B" but it still getting reference of "A" , my code is as bellow ....

function setData(aid, pid, strTitle, strDesc, strScreenShot) {
addthis_ui_config =
{
services_compact: 'facebook, tweeter, myspace, igoogle, netvibes, windows, dashboard, more'
}
addthis_share_config =
{
url: 'http://www.xyz.com?aid=' + aid + '&pid=' + pid,
title: strTitle,
description: strDesc,
swfurl: "",
width: "560",
height: "340",
screenshot: 'http://www.xyz.com/' + aid + '/' + strScreenShot
}
addthis.button("#btn1", addthis_ui_config, addthis_share_config);
return true;
}

but it is working first time only,

Please reply me ASAP
Thank You