How do I register my project with UberDist to get my distribution goal called?
Until a custom tag is integrated in the plugin (like report plugin for example), you must call the registerProject tag from the UberDist taglib. The snippit below shows an example:

Note that the property gets are "optionnal" at this point but doing it there allows you to use them freely in your maven script while building your distribution.

<postGoal name="uber-dist:init">
    <udist:registerProject name="${pom.artifactId}" description="My distribution"/>
		<maven:get plugin="maven-uberdist-plugin" 
            property="maven.uber.dist.assembly.dir" var="dist.assembly.dir" />
		<maven:get plugin="maven-uberdist-plugin" 
		    property="maven.uber.dist.dir" var="distribution_dir" />

Using the ${} is a very good practice. This is the value that will be used as default when the tag will be available. This name is then used as
How do I create my distribution with UberDist?
You have to add a goal in your project named: [registered_name]:prepare-dist-filesystem. where [registered_name] is the name you supplied when registering with the plugin.