What I would recommend you do is disable the admin area integration by commenting out this line:
Code:
define('USE_ADMINCP_BRIDGE', true);
To:
Code:
##define('USE_ADMINCP_BRIDGE', true);
By doing this, you separate users using the WP admin area (wp-admin) from VB users. Users in the WP admin area would have separate logins. VB users will be able to comment on WP posts and depending on your theme you should also see their avatars.