WordPress 3.0 and bbPress: deep integration fails

Hello,
Sharing a database between WordPress 3.0 and bbPress seems to work fine, but deep integration as outlined on https://bbpress.org/documentation/integration-with-wordpress/ seems to screw the registration process in bbPress:

Deep integration requires adding require_once(dirname(__FILE__) . '/path/to/wp-load.php'); to bb-config.php, but this seems to cause the following behaviour:

When registering a user via bbPress on a shared database (bbpress uses wp_users) the following error is given:

Email is required

More information:
https://bbpress.org/forums/topic/wp-30-beta-2-integrated-user-registration

Any thoughts? This might affect all users with ‘deeply integrated’ bbPress installs.