How to reference a custom type via refid?

[Carlton Brown]

In a custom type, if I want to define it and reference it later, what's the
Java code to do that?

<my:type refid="foo" name="alpha"/>

<my:task>
    <my:type name="omega">
      <my:type refid="foo"/>
    </my:type>
</my:task>

The MyType class extends org.apache.tools.ant.types.DataType and it has a
method addConfigured(MyType).  But the above sample code creates a new
my:type instance, it does not seem to dereference to foo.

I read the docs but I didn't recognize anything that explains this.

Thanks in advance,

Carlton