hello 1900JLS400 , your keys is looks long or short ?
I think long key is 46mm , short key is 41mm.
your key is sub key or a key with remote control.
I find a lot of replacement remote key shell on the web of keymam.
http://www.keymam.com/products.asp?Channel=36
http://www.keymam.com/product_view.asp?pid=964