This is far from an ideal solution, but it is at least a solution. I recognize that it won't be acceptable to some, even as a temporary solution. It will work for me for the short term, but I really hope WD can fix this fast.
- login to the web interface on your MBWE
- click on Advanced mode
- click on Users
- click on Folder Share Permissions
- for the first shared folder that you need to make available, click on the edit icon on the right
- check the Enable box for Public Access
- click on Submit
- repeat steps 5-7 for every share you need
- login to your MBWE using SSH (you may need to enable this in the web interface if you haven't already)
- cd /shares (it will probably be there already)
- cd into each share directory
- chmod 777 * (change the permissions on every directory in the share to be world readable/writable/executable)
Now you should be able to connect to your MBWE as Guest and access your shares.
As I said, not an ideal solution, but it's working for me. I installed Lion before knowing about this problem, and I have files on my MBWE that I simply can't lose access too, even for a short period.