MacOS – After enabling File Vault, OS X doesn’t mount disk automatically anymore

I have an external 2 TB LaCie drive connected via FireWire 800 to my MacBook Pro (8,2 – early 2011 model), which runs OS X 10.8.5. It has one big partition which is a Time Machine target, and the backup is encrypted. My Macintosh HD itself is also encrypted.

Before, I could just plug in the drive and it would automatically mount all the volumes on it, but ever since I've enabled encryption and started a new Time Machine backup, the disk is not mounted automatically anymore – I have to go into Disk Utility and manually unlock it:

Sometimes I even have to enter my master password for that drive.

Of course, that's not really practical: it's a backup drive and therefore should be mounted automatically every time it's plugged in.

I have not changed my /etc/fstab to prevent it from mounting, nor have I changed any configuration regarding mounting or Time Machine. Here's the diskutil list output for the sake of completeness:

/dev/disk0
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *121.3 GB   disk0
   1:                        EFI                         209.7 MB   disk0s1
   2:          Apple_CoreStorage                         120.5 GB   disk0s2
   3:                 Apple_Boot Recovery HD             650.0 MB   disk0s3
/dev/disk1
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                  Apple_HFS Macintosh HD           *120.1 GB   disk1
/dev/disk2
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:      GUID_partition_scheme                        *2.0 TB     disk2
   1:                        EFI                         209.7 MB   disk2s1
   2:          Apple_CoreStorage                         2.0 TB     disk2s2
   3:                 Apple_Boot Boot OS X               134.2 MB   disk2s3
/dev/disk3
   #:                       TYPE NAME                    SIZE       IDENTIFIER
   0:                  Apple_HFS Data                   *2.0 TB     disk3

How do I get OS X to mount my volume automatically again?

_{NB: I also noticed that as soon as I eject the drive, it doesn't spin down anymore. It used to do that before though – now I have to shut it down with the hardware switch.}