Ask a Celestron dealer if they have the following sitting on their shelves
http://www.celestron.com/c3/product.php?ProdID=314
It has a lock ring to allow for rotating of the visual back. You may have to search around if anyone has one in stock as it has been discontinued and there doesn't appear to be a replacement from Celestron.
However, I don't believe it has a compression clamp so you may be better off with a different product. You don't want one that causes vignetting though.