Thank you but no, the ones I saw are dish shaped with a slot at the back and the centre button with a shank sits inside. It is possible to remove the outer ring if the button is not sewn down.
I bought Sew magazine and it has an article on embroidered buttons, the metal ring is around the fabric but it does not mention where to get the kits. If i could buy the backer piece, I'd use cover buttons for the inside.
It also had 2 patterns, one for cape (!where have I just seen one?) the other for a princess seam dress with different cup sizes - sadly it was the one with smaller sizes.
If no one can help, I will write to the magazine, but I'm not as hopeful of help from them as I am from here! They seem to be associated with Simplicity, like Sewdirect.