Instructions on how to trigger an sbt-web plugin

The thing that's been giving me by far the most trouble is figuring out how to trigger the plugin. The part I'm still not quite sure about is whether it's true that this is the most common way to trigger an sbt plugin:

    myTask in Assets <<= (myTask in Assets).triggeredBy(compile in Compile)

I don't see this code in any of the existing plugins, but I also can't figure out any other way to get Play to execute my plugin. Is there something else we should depend on that Play might hook into?