How to configure remote respository authentication in tycho-p2-extras-plugin mirror goal?

Question

I have a private repository which I can access using HTTP basic auth. I would like to create a local mirror of that repository using the tycho-p2-extras-plugin mvn plugin. I have added the credentials in the ~/.m2/settings.xml using both the repository id and URI:

<settings xmlns="http://maven.apache.org/SETTINGS/1.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/SETTINGS/1.0.0 https://maven.apache.org/xsd/settings-1.0.0.xsd">
    <servers>
        <server>
            <id>test-repo</id>
            <username>*********</username>
            <password>*********</password>
        </server>
        <server>
            <id>https://test-repo-uri.com/path/to/repo</id>
            <username>*********</username>
            <password>*********</password>
        </server>
        <server>
            <id>test-repo-uri.com</id>
            <username>*********</username>
            <password>*********</password>
        </server>
    </servers>
</settings>

This is the mirroring pom.xml:

<?xml version="1.0" encoding="UTF-8"?>
<project xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd" xmlns="http://maven.apache.org/POM/4.0.0"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
    <modelVersion>4.0.0</modelVersion>
    <groupId>test-repo-mirror</groupId>
    <artifactId>test-repo-mirror</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <build>
        <plugins>
            <plugin>
                <groupId>org.eclipse.tycho.extras</groupId>
                <artifactId>tycho-p2-extras-plugin</artifactId>
                <version>4.0.9</version>
                <executions>
                    <execution>
                        <phase>prepare-package</phase>
                        <id>mirror-target-platform</id>
                        <goals>
                            <goal>mirror</goal>
                        </goals>
                    </execution>
                </executions>
                <configuration>
                    <source>
                        <repository>
                            <id>test-repo</id>
                            <url>https://test-repo-uri.com/path/to/repo/</url>
                            <layout>p2</layout>
                        </repository>
                    </source>
                    <destination>${project.build.directory}/repo-mirror</destination>
                    <followStrictOnly>true</followStrictOnly>
                    <includeOptional>false</includeOptional>
                    <includeNonGreedy>false</includeNonGreedy>
                    <latestVersionOnly>true</latestVersionOnly>
                    <includePacked>false</includePacked>
                </configuration>
            </plugin>
        </plugins>
    </build>
</project>

yet no matter what I try the mirroring attempt fail with authentication error. Am I making some sort of error? Or is it not supported?