It looks like I solved it. This one was easy. If it’s still of any help, here it goes:
//in method
private BufferedImage getImage(Vector2f scaleFactors){
//…
int textX = (int)( desiredX/2 - b.getCenterX() );//kernelSize/2;
int textY = (int)( desiredY/2 - b.getCenterY() );//g2d.getFont…
//…
}