Adobe Flash Builder 4 cannot introspect a PHP file with underscores in its filename. This behavior adheres to coding conventions in Zend framework. See the Zend framework coding-standard for details.
These conventions are derived from a much older project, PEAR. PEAR standards are widely used throughout the PHP community, and adopted by a number of other PHP projects. By adhering to these naming conventions, developers can ensure that they are compatible with other projects. And they will (most likely) avoid naming collisions.
