I want to display a 2d image at the top of the GUI for a M3G app. I want to scale the image according to the screenwidth and the height of the mobile device. I can't find any way to scale the image. I try this approach, but it just cuts a piece from the image:

sourceH = Image.createImage("/res/header.jpg" );
sourceH = Image.createImage(sourceH,0,0,300,100,Sprite.TRANS_NONE );