SMF Forum to Vbulletin without Password Lose & Custom Addons For Vbulletin

We have a very large SMF Forum. We want to move it to Vbulletin without losing any data. As we know users need to reset their passwords. Many of our users don't remember their passwords. So we need to keep old SMF database and write a custom login system to new Vbulletin forum. Once the user confirms his/her password on the old forum that user will create a new password in Vbulletin. So we won't lose players and we will be sure they are the correct person. 1) Move all topics, attachments, images, members to VBULLETIN 2) Write a custom login system to check users authentication and set a new password on Vbulletin. 3) For Vbulletin, we want to add Facebook Login as well Stats * 3,800,000 Posts * 396,000 Topic * 560,000 Users