Oracle Weblogic ant script

Hi everybody

I searched on the internet for how to make ant tasks for BEA weblogic server using weblogic workshop
I found that there are aready tasks made for weblogic for example
<wlserver>

The problem is that when I try to use it in the build.xml in my weblogic workspace I cannot find the <wlserver task
I find something called <wlstart and <wlstop

are those the right tasks for weblogic?
and how can I install and run applications using ant on weblogic ?