In the "configuration" section of the maven flex plugin declaration you can declare the component manifest. This declaration can solved a unexceptable error of the compiler, when instanciate the following classes and get a could "Could not resolve mx:xxx to a component implementation." error.
There is a post about this issue on sf.net at https://sourceforge.net/forum/forum.php?thread_id=2860770&forum_id=680829
...
<configuration>
<componentManifests>
<componentManifest>
<manifestFile>src/main/resources/mxml-manifest.xml</manifestFile>
<manifestURI>http://www.adobe.com/2006/mxml</manifestURI>
</componentManifest>
</componentManifests>
</configuration>
...
Be sure to place the mxml-manifest.xml in the corresponding directory
With the same mechanism you can also add your own componentManifest. ( can be useful for map all your own classes on a single namespace, such as mx: for all framework component )