Cannot Log in with Active Directory Identity after enable filevault

We have network environment that uses Active Directory for log in.

I have successfully setup the Log in with Active Directory with Lion.

However, after I run the FileVault, the first initial log in screen no longer

gives me the option to type in Username and Password. It only allow to log in

with the Local Account.

To able to log in with Network Identity authenticate with Active Directory,

1st. Log in local Account & password

2nd Log off the local account

3rd Type in the ID and password to login with ID.

I think this is a bug. Anyone has the same issues?