Here's what I add to my pom.xml if I want to deploy the artifact to my Maven repo:
<distributionManagement>
<repository>
<id>internal</id>
<url>http://HOST:PORT/archiva/repository/internal/</url>
</repository>
<snapshotRepository>
<id>snapshots</id>
<name>Archiva Managed Snapshot Repository</name>
<url>http://HOST:PORT/archiva/repository/snapshots/</url>
<layout>default</layout>
</snapshotRepository>
</distributionManagement>
<repositories>
<repository>
<id>snapshots</id>
<url>http://HOST:PORT/archiva/repository/snapshots/</url>
<releases>
<enabled>false</enabled>
</releases>
<snapshots>
<enabled>true</enabled>
</snapshots>
</repository>
</repositories>