Oomph import Eclipse projects from disk (not using source control)

Question

I'm trying to use Oomph to setup an Eclipse dev environment, and import some (source) projects from the disk, from a given root folder. For this I'd like to use a variable to mark where this root folder is (prompt the user for it), and from there let Oomph discover the required projects inside that folder. Since I haven't found any docs on this, here is what I tried:

<?xml version="1.0" encoding="UTF-8"?>
<setup:Product
    xmi:version="2.0"
    xmlns:xmi="http://www.omg.org/XMI"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:projects="http://www.eclipse.org/oomph/setup/projects/1.0"
    xmlns:setup="http://www.eclipse.org/oomph/setup/1.0"
    xmlns:setup.p2="http://www.eclipse.org/oomph/setup/p2/1.0"
    xsi:schemaLocation="http://www.eclipse.org/oomph/setup/projects/1.0 http://git.eclipse.org/c/oomph/org.eclipse.oomph.git/plain/setups/models/Projects.ecore"
    name="my.product"
    label="My Product">
    <setupTask
        xsi:type="setup:InstallationTask"
        id="installation"/>
    <version name="neon"
        label="Neon"
        requiredJavaVersion="1.7">
        <setupTask
            xsi:type="setup.p2:P2Task"
            label="foo">

            <!-- Requirements and repositories for the dev env to work -->

            <!-- Here is a project that I'd like to import -->
            <requirement name="com.mycompany.myproject"/>

        </setupTask>

        <!-- This task should locate the project to import -->
        <setupTask
            xsi:type="projects:ProjectsImportTask">
            <sourceLocator
                rootFolder="${my.sourceroot}/eclipse-plugins/"
                locateNestedProjects="true"/>
        </setupTask>

        <!-- The variable to mark the root folder -->
        <setupTask
            xsi:type="setup:VariableTask"
            id="my.sourceroot"
            type="FOLDER"
            name="root folder"
            label="root folder">
        </setupTask>

        <description>My Product for Neon.</description>
    </version>
    <description>My Product provides cool stuff.</description>
</setup:Product>

When trying to setup the IDE using the Oomph app it doesn't ask for the root folder, and obviously errors not finding the project I'd like to import.

Question: What's the right way to do this? Any docs or tutorials (for dummies) would be also greatly appreciated on this.