Stuck on custom wagon and plexus

[Edelson, Justin]

I'm writing a Maven plugin that requires a customized version of the SCP Wagon. 
While I've written a number of plugins in the past, this is the first time I've 
tried to create a Plexus component and I seem to be stuck.

Here's what I've done:
* In one project, I have a class (...JschTunnelWagon), an interface 
(...TunnelWagon), and a components.xml file (in src/main/resources/plexus) with 
this content:
<component-set>
  <components>
    <component>
      <role>org.apache.maven.wagon.Wagon</role>
      <role-hint>ssh-pf</role-hint>
      
<implementation>com.mtvi.plateng.maven.wagon.JschTunnelWagon</implementation>

[other configuration]

    </component>
  </components>
</component-set>
* In my plugin project, I depend upon the first project and do this:
    /**
     * The Tunneling Wagon.
     * 
     * @parameter expression="${component.org.apache.maven.wagon.Wagon#ssh-pf}"
     * @required
     * @readonly
     */
    private TunnelWagon wagon;

When I try to execute my mojo, I get this error:
Component descriptor cannot be found in the component repository: 
org.apache.maven.wagon.Wagonssh-pf.

With -X, I see this:
Caused by: org.codehaus.plexus.component.composition.CompositionException: 
Composition failed of field wagon in object of type 
com.mtvi.plateng.maven.utils.TunnelCreatorMojo because the requirement 
ComponentRequirement{role='org.apache.maven.wagon.Wagon', roleHint='ssh-pf', 
fieldName='wagon'} was missing

I'm sure I'm missing something simple, but if anyone can help, I'd appreciate 
it.

Thanks,
Justin