Unrecognized migration I am using this example: https://gist.github.com/2596787 as a base for importing some static HTML to a Drupal 7 fresh install.  Using drush ms:

Group:                Total  Imported  Unimported  Status  Last imported

HtmlfilesNodeMigration

HtmlfilesNode         2046   0         2046        Idle    2013-01-23 13:58:01


I can see that the Migration class seems to be setup.  However when I go to run the migration from drush I get:

Unrecognized migration: HtmlfilesNodeMigration                           [error]


Trying through the UI, I get 

Fatal error: Class 'HtmlfilesNodeMigration' not found


Any ideas, pointers etc would be a great help.  I can post the info/module/inc files I am using if needed.
I've made a bit of progress.  I had created the HtmlfilesNodeMigration class outside of the actual hook_migrate_api function.

So instead of:

return $api;

}

class HtmlfilesNodeMigration extends Migration {
//code
}


I needed: 

return $api;
class HtmlfilesNodeMigration extends Migration {


  }

}