I encrypted a Lion partition called "Storage" and it worked perfectly. I needed to decrypt it momentarily because I had some issues, but now I want to encrypt the same volume again and it says "The Core Storage-targetvolume is already encrypted".
Other partitions work fine with decrypting and encrypting, just not this one. Perhaps it has something to do with my home-folder being on the "Storage" partition, but it is strange that encrypting worked the first time and now it doesn't anymore after I decrypted it.