Maven Filtering

According to http://maven.apache.org/shared/maven-filtering/ I can define

<properties>
<projectBuildDirectory>\${project.build.directory}</projectBuildDirectory>
</properties>

and I should expect to see

${project.build.directory}

when the property projectBuildDirectory is used, but instead I get

\D:\Users\Eric\Software\Project\Repositories\csharp-windows-elevate\target

Am I going insane, is this a bug in Maven, or is the documentation wrong?

Is there some other way to escape the filtering?

Cheers, Eric