That's very easy to do in FCP, but I don't know if FCE has the same features or not. This is how I did it in FCP though.
1. Place the video on V1.
2. In the Viewer window click on the button in the lower right hand corner that looks like a film frame w/the letter "A" on it. Then select Text->Lower 3rd.
3. Go to the "controls" tab and down towards the bottom find the drop down menu called "background" and change it to "solid." By default it is black but you can change it to whatever color you want.
4. Change the text to what you want it to be and put it on V3.
5. In the Viewer window click on the same button where the text tool is found and choose "custom gradient". By default the gradient should be white on the left hand side and fade to black on the right hand side. If it doesn't look like this then, w/the custom gradient still loaded in the Viewer go to the "controls" tab and make it start w/white and end w/black.