I'm trying to add a png with a 24 bit transparency but when I do so it is no longer transparent. 8 bit transparency works fine, but I require the extra alpha detail from 24 bit. Does Acrobat support it?
Sure...Go to PShop and make the image the size you want, ensuring it has a transparent background. Save As a PDF (usually press quality without colour conversion).
Go back into Acrobat, make a button on your document where you want to place the graphic. Select "Icon Only" from "Options" from "Button Properties". Browse for your brand new PDF file you made and Bingo....you should now have your graphic in place on your document.