Unfortunately, FCP does not have its own motion tracking capabilities...You will have to get third party plugins like Lyric Plugins or Boris Fx to perform this function within FCP.
http://www.lyric.com/fcp-plugins/tracking.htm
http://www.borisfx.com/fx/
If you have Motion or After Effects you might as well use those since the concept of motion tracking is similar no matter what program you use.
If you insist on using FCP without the assistance of a motion tracker, another option would be to keyframe the position of your matte 30 times per second...not recommended.