Make sure you have the forge Maven2 repository reference and dependency definition in the root pom.xml of your project.
<repositories>
<!-- SNIP -->
<repository>
<id>hippo-maven2-forge</id>
<name>Hippo Maven 2 Forge</name>
<url>http://maven.onehippo.com/maven2-forge</url>
</repository>
<!-- SNIP -->
</repositories>
<!-- SNIP -->
<dependencyManagement>
<!-- SNIP -->
<dependencies>
<!-- SNIP -->
<!-- NOTE: You should set a property named 'forge.sforce-comps.version' to a version of this plugin! -->
<dependency>
<groupId>org.onehippo.forge</groupId>
<artifactId>sforce-comps</artifactId>
<version>${forge.sforce-comps.version}</version>
</dependency>
<!-- SNIP -->
</dependencies>
<!-- SNIP -->
</dependencyManagement>
And add the following dependency reference into your Hippo Web Application module subproject (e.g, site/).
<dependencies>
<!-- SNIP -->
<dependency>
<groupId>org.onehippo.forge</groupId>
<artifactId>sforce-comps</artifactId>
</dependency>
<!-- SNIP -->
</dependencies>
Now, you're ready to use the plugin!