Register Ant task in build.xml

Insert the following lines into your build.xml file to register the Externalizer Ant task. Adjust the $externalizer.lib directory.

<taskdef name="externalizer" 
        classname="de.cl.externalizer.Externalizer" 
        classpath="${externalizer.lib}/externalizer.jar"/>

Register Ant task in eclipse

First we have to add the jar into the ant environment:
Go to eclipse preferences Window -> Preferences.
Select Ant \ Runtime.
To add jar in global entries, select Global Entries -> Add JARs... and choose the externalizer-x.x.jar.

And now we can register the task:
Click the Tasks-Tab and select Add Tasks.... Now you have to select a name, the newly added externalizer-x.x.jar file and the Externailzer.class, like in the following figure:

Use Ant Task

Afterwards you can use the Externalizer Task in your target. See -> Documentation

Run Ant target

Start your target with:

[ant-directory]\bin\ant.bat -file [build.xml] [targetname]