Maven Checkstyle configLocation ignored

Attempting to set a custom checkstyle configuration in the maven pom according to the guidelines on the apache site isn't working in a very simple case.

I created a project, MyProject, using the directory layout recommended by Maven (i.e. src/main/java/, src/main/resources), a single file MyClass.java:

package com.myproject;

public class MyClass {

   public static void main(String[] args) {
      System.out.println("This line is longer than 80 characters which returns an error in sun_checks.xml, however my_checks.xml allows for much longer lines and will not return a long line error.");
   }
}

an empty checkstyle file, my_checks.xml:

<?xml version="1.0"?>
<!DOCTYPE module PUBLIC
    "-//Puppy Crawl//DTD Check Configuration 1.2//EN"
    "http://www.puppycrawl.com/dtds/configuration_1_2.dtd">

<module name="Checker">
    <property name="severity" value="warning"/>
    <module name="TreeWalker">
    </module>
</module>

and a pom file according to the specifications in the guide:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">

    <modelVersion>4.0.0</modelVersion>
    <groupId>com.myproject</groupId>
    <artifactId>A_Project</artifactId>
    <name>A Project</name>
    <version>1.0.0</version>

    <reporting>
    <plugins>
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-checkstyle-plugin</artifactId>
        <version>2.8</version>
        <configuration>
          <configLocation>my_checks.xml</configLocation>
        </configuration>
      </plugin>
    </plugins>
  </reporting>
</project>

Running 'mvn -X checkstyle:checkstyle' is using the sun_checks.xml (default) instead of using the configuration in the my_checks.xml file, which can be seen by both the resulting checkstyle errors and the debug output (ex. '[DEBUG] request.getConfigLocation() config/sun_checks.xml').

I know the my_checks.xml is valid because the checkstyle.config.location can be changed in the properties using the strategy outlined by Carboni in a previous stack overflow post, but this causes issues when moving to multi-module projects and differs from the 'official' apache maven checkstyle instructions.