On live cd unable to execute under encrypted home

Hello,

For almost a month I struggle with the following bug/missing feature of the Ubuntu live cds (100% reproducible for Karmic and Lucid):
- boot from live cd
- create a user with encrypted home:
$ sudo adduser --gecos "" --encrypt-home testuser
- su to the new user
$ su testuser
$ ecryptfs-mount-private
- copy a (any) binary into the home folder of the new user and run it:
$ cd ~
$ cp /bin/ls ./
$ ./ls
ls: Function not implemented
$ echo $?
126

Related to this: trying to list the contents of the encrypted home folder using "ls -l" prints for every entry within the folder the same message but no error return code. ($? is 0)

The behaviour holds if home is stored in a casper-rw partition (the case of a live usb stick based upon grub2 and the iso image of the live cd). Data within the home folder is preserved between reboots, but changes become available only after the next reboot. I posted the issue on the ubuntu developer mail list and linuxquestions.org but for now no answers.

For what I can tell, it seems that the home folder is not fully decrypted/fully accessible, but the reason for this alas escapes me.

Any suggestions will be highly appreciated,
Linus