sprite & image - j2me

[Jeff]

midp 2.0
Java SE 5.0
J2ME version 2.2

I'm trying to create an image based on javax.microedition.lcdui.Image
I wish to fill the image with graphic created by the code and not use a real
image... because I want the image to change during program execution.... I
want the image to display a circle filled with a color... I guess there is
no such thing as a circle image so I thought first create a layer with
Alpha=0% (transparent) and then a layer above it containing the
circle...... - giving the impression of a circle image, the corners of the
image object melt into the background

I want this image to be put into a sprite

I'm not sure how to create such an image...

Please if you have any tips about this then tell me, and links to examples
solving this problem is very welcome

Jeff