You just have to bind an execution of the plugin to a phase (e.g. "install" in your example):
<profile>
<id>my-profile</id>
<build>
<plugins>
<plugin>
<artifactId>maven-release-plugin</artifactId>
<version>2.4.1</version>
<executions>
<execution>
<phase>install</phase>
<goals>
<goal>prepare</goal>
</goals>
<configuration>
<updateWorkingCopyVersions>false</updateWorkingCopyVersions>
</configuration>
</execution>
</executions>
</plugin>
</plugins>
</build>
</profile>