encryption: How to migrate from losetup to dm-crypt? (11.1)

…and/or if this is possible at all?

I have already encrypted files, but since I am moving from opensuse10.3+losetup (actually losetup-aes from 10.2) to opensuse 11.1+dm-crypt I need a way to get access to old files (I cannot re-encrypt them again).

I accessed the files (!) in such way:
losetup -e aes-256 -G gpg_home -K gpg_key /dev/loop0 my_file

In OS 11.1 I try to do this:
losetup /dev/loop0 my_file

and then
gpg --homedir gpg_home --decrypt gpg_key | cryptsetup --hash sha512 --cipher aes-cbc-plain --key-size 256 create mapped_img /dev/loop0

After the latter command I get the error:
Command failed: reload ioctl failed; invalid argument

I already have read that this might be caused by lack of modules, so I did:
modprobe dm-mod
modprobe dm-crypt
modprobe aes_generic
modprobe sha256_generic
modprobe sha512_generic
modprobe sha1_generic

No difference for cryptsetup though.

I would appreciate any tips/help/etc :-).


PS1. I rely on this doc:
Encrypted Filesystems - openSUSE

PS2. I am not sure about the number, I mean if I used aes 256 before what hash should I use now? However this is for later…