If you find a Horn of American Dealer, they will be able to get you the correct insert. I had a Bernina 440QE for about 10 years. I just traded up to a Bernina 580. I have a Horn Quilter's Delight Table, which isn't made any longer. But they were able to get me the insert for it.
I traded my machines at the AQS Show in Lancaster, PA in March. I bought mine from Hinkletown Sewing. They are located in Ephrata, PA. They do ship though because I live about 4 hours from them and they shipped mine to me. And they are awesome to work with. They have good prices too!
Hope that helps!