You don’t need a 64-bit bridge CPU, you just need a 32-bit CPU (or less) that understands 48-bit LBAs.
That said, if your bridge IC has a firmware update, then that may be all you need.
For example, the following chip is a common one:
http://files.hlama.net/uploads/posts/1292949243_jmicron_jms539.jpg
Here is a thread where the OP has resolved a 3TB recognition problem in his USB enclosure:
http://www.tomshardware.com/forum/274015-32-external-usb3-drive-shows-devices
