As I read http://support.apple.com/kb/HT4790 it appears that apple not on has you keep that key to unlock such things but since it's on time machine, rather than guess why not make the call to apple. This work appears to be worth it.
My bet is a call to apple is cheaper than http://www.drivesavers.com
I always want to ask but at the risk of upsetting folk, why do folk encrypt without a backup in the clear that one can just copy their stuff back in?
Even I have 2 copies on HDDs, and a few select items synced with a cloud and a final can't lose this ever on all the prior backups noted on a few memory sticks.
So, here's what happened. I have an early 2008 black macbook. it was running lion. Then, last saturday, I had to force it to turn off and, after that, I wasn't being able to sign into my account again. It entered an infinite loop. I tried everything, but i ended up formatting my macbook hd and performed a clean install of lion. I had it all backed up with time machine on an external hard drive, so i didn't worry much. The problem is, my account was encrypted with legacy filevault. After the fresh intall of lion, i finally got my macbook to work again, but now i can't restore the files from my previous account. I have no other macs and i can't find any sparsebundle files on my time machine backup. What can I do to restore the files from my legacy filevaulted account on my external hard drive? Please help. I have a lot of files from two years of university, and i can't lose them.