Così ?
<BODY onLoad="Esegui();">
<Script Language="Javascript">
function Esegui()
{
d.write('<FORM ACTION="../../../cgi-bin/cognos.cgi" METHOD="post" NAME="srv">');
d.write('<input type="hidden" name="b_action" value="xts.run">');
d.write('<input type="hidden" name="m" value="portal/launch.xts">');
d.write('<input type="hidden" name="ui.tool" value="CognosViewer">');
d.write('<input type="hidden" name="ui.action" value="run">');
d.write('<input type="hidden" name="run.prompt" value="false">');
window.document.srv.submit();
d.write('</FORM>');
}
</Script>