How do you migrate a FileVault-protected account from a Time Machine backup?

Recently the hard drive on my Macbook Pro died and had to be replaced. Prior to the hard drive's failure, I had backed up my sole user account to an external hard drive using Time Machine. When setting up the new hard drive for the first time, I used Migration Assistant to restore my user account to my new hard drive. However, when I go to log in to the user account I transferred over, I encounter the following error: "You are unable to log in to the FileVault user account "User" at this time. Log in failed because an error occurred." I am absolutely positive I entered the correct password.

My next step was to boot from the install disc and repair the hard drive and permissions. The same problem occurred when I tried to login.

Then I wiped the hard drive and installed Snow Leopard normally without attempting to migrate anything. After the installation, I attempted migration, only to see an error message under the "Users" heading, saying, "User accounts protected by FileVault can't be transferred." Looking at the backups I have on my external hard drive, I cannot see any of my individual files, which I could when logged in on my previous hard drive.

I have scoured the internet for possible solutions but none seem to fit the situation. The techs at the Genius Bar tried a few things beyond my level of technical know-how and were unsuccessful, and they did not seem too optimistic about my chances. They mentioned that I should consider a visit to a data recovery center if I could not find any way to fix this issue.

This is immensely important, considering my FileVault-protected account nestled away in the Time Machine backups on my external hard drive contains all of my work. While I am willing to make the trip to the data recovery center, I would like that to be a measure of last resort. Any help you can provide will be greatly appreciated!