@Estel,

About FSCK_HOME: /etc/event.d/rcS-late sources /etc/default/mount-opts, which kernel-power patches so as to source /etc/kernel-power/pre-mount.

On pre-mount FSCK_HOME is checked and if true, the first partition on mmcblk0 with type 83 will be fsck'ed setting the type explicitly to ext3.

So you'd need to patch that script either to suite your partitioning scheme or to make it more flexible..