Make in a Maven project disregards <build><directory>

Greetings -- I'm using a property in my pom.xml to have separate build directories around for different versions of Scala.  Looks like,


    <profiles>
        <profile>
            <activation>
                <activeByDefault>true</activeByDefault>
            </activation>
            <id>Scala-2.7.5</id>
            <properties>
                <scala.version>2.7.5</scala.version>
            </properties>
        </profile>
        <profile>
            <id>Scala-2.8.0-SNAPSHOT</id>
            <properties>
                <scala.version>2.8.0-SNAPSHOT</scala.version>
            </properties>
        </profile>
    </profiles>

    ...


    <build>
        <sourceDirectory>src/main/scala</sourceDirectory>
        <directory>target-${scala.version}</directory>