In maven, how to override plugin configuration in settings.xml - maven

Question

I want to override a particular plugin configuration that's defined in the pom.xml. I don't want to modify the pom.xml for various reasons. Is there a way to define a config attribute for that plugin in settings.xml that override corresponding pom.xml plugin config?
In the below example, you'll notice that the plugin xx-plugin is defined in profile1 in pom.xml. In my settings.xml I've already defined profile2 to override property prop1 from pom.xml. But how to override config3. I apologize if this is a silly question. I am a little new to maven.
This is what my pom.xml looks like:
<profile>
<id>profile1</id>
<activation>
<activeByDefault>true</activeByDefault>
</activation>
<build>
<plugins>
<plugin>
<groupId>com.xx.yyy</groupId>
<artifactId>xx-plugin</artifactId>
<executions>
<execution>
<id>xx-install</id>
<phase>install</phase>
<goals>
<goal>xx-install</goal>
</goals>
<configuration>
<config1>AAA</config1>
<config2>BBB</config2>
<config3>CCC</config3> <!-- I want to override this with value DDD -->
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
</profile>
This is what my settings.xml looks like:
<profile>
<id>profile2</id>
<activation>
<activeByDefault>true</activeByDefault>
</activation>
<properties>
<prop1>overriden-value</prop1> <!-- This works -->
</properties>
<!-- Somehow override config3 here -->
<!-- <config3>DDD</config3> -->
</profile>

Answer 1

AFAIK you can only override properties with settings.xml profiles. You'd have to change your plugin's configuration to use a property instead of a fixed value:
<!-- define your property -->
<properties>
<prop1>CCC</prop1>
</properties>
<profile>
<id>profile1</id>
<activation>
<activeByDefault>true</activeByDefault>
</activation>
<build>
<plugins>
<plugin>
<groupId>com.xx.yyy</groupId>
<artifactId>xx-plugin</artifactId>
<executions>
<execution>
<id>xx-install</id>
<phase>install</phase>
<goals>
<goal>xx-install</goal>
</goals>
<configuration>
<config1>AAA</config1>
<config2>BBB</config2>
<config3>${prop1}</config3> <!-- I want to override this with value DDD -->
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
</profile>
Remember that profiles with activeByDefault set to true will get deactivated if any other profile gets activated in your build invocation. See http://maven.apache.org/guides/introduction/introduction-to-profiles.html

Answer 2

If you do not want to change the pom.xml for a plugin you can set the configuration as JVM parameter when running maven as stated in the Generic Configuration chapter of the Maven Guide to Configuring Plugins.
Example:
mvn my-plugin:my-goal -Dplugin.property=ABC
Example for the wildfly plugin (this is where I needed it and did not want to change the pom.xml of a demo project when deploying to a server group in a domain context):
mvn clean install wildfly:deploy -Dwildfly.serverGroups=<server-group-name>
The maven documentation also states that most plugins define help goals to explain users how to configure them.
Exaple for the wildfly plugin:
mvn wildfly:help -Dgoal=deploy -Ddetail