[Galaxy S I9000 Q&A, Help & Troubleshooting] Thyrador:
current state is as following:

/etc/init.d/S01init

#!/system/bin/sh

# remount
busybox mount -o rw,remount /

#create paths
mkdir /sd
mkdir /mnt/sdcard_ext
chmod 0775 /mnt/sdcard_ext

#duplicate, delete and linking original files
cp /init.rc /init.rc_original
cp /etc/voId.fstab /etc/voId.fstab_original

rm /init.rc
rm /etc/voId.fstab

ln -s /etc/init.d/scripts/init.rc /init.rc
ln -s /etc/init.d/scripts/voId.fstab /etc/voId.fstab

#set init.rc vars
#export EXTERNAL_STORAGE2 /mnt/sdcard_ext
#symlink /mnt/sdcard /sd/sdcard
#symlink /mnt/sdcard_ext /sd/sdcard_ext

#linking new mounting paths
ln -s /mnt/sdcard /sd/sdcard
ln -s /mnt/sdcard_ext /sd/sdcard_ext

busybox mount -o ro,remount /

### end

custom init.rc

on early-init
start ueventd

on init

sysclktz 0

loglevel 3

# setup the global environment
export PATH /sbin:/vendor/bin:/system/sbin:/system/bin:/system/xbin
export LD_LIBRARY_PATH /vendor/lib:/system/lib
export ANDROID_BOOTLOGO 1
export ANDROID_ROOT /system
export ANDROID_ASSETS /system/app
export ANDROID_DATA /data

export EXTERNAL_STORAGE /mnt/sdcard
export EXTERNAL_STORAGE2 /mnt/sdcard_ext
export USBHOST_STORAGE /mnt/sdcard/usbStorage

export ASEC_MOUNTPOINT /mnt/asec
export LOOP_MOUNTPOINT /mnt/obb
export BOOTCLASSPATH /system/framework/core.jar:/system/framework/bouncycastle.jar:/system/framework/ext.jar:/system/framework/framework.jar:/system/framework/android.policy.jar:/system/framework/services.jar:/system/framework/core-junit.jar

# Backward compatibility
symlink /system/etc /etc
symlink /sys/kernel/debug /d

# Right now vendor lives on the same filesystem as system,
# but someday that may change.
symlink /system/vendor /vendor

# create mountpoints
mkdir /mnt 0775 root system
mkdir /mnt/sdcard 0000 system system
mkdir /mnt/sdcard_ext 0000 system system

# Create cgroup mount point for cpu accounting
mkdir /acct
mount cgroup none /acct cpuacct
mkdir /acct/uid

#add booting sound property
setprop audioflinger.bootsnd 1

# Backwards Compat - XXX: Going away in G*
symlink /mnt/sdcard /sd/sdcard

mkdir /system
mkdir /dbdata 0771 system system
mkdir /data 0771 system system
mkdir /cache 0770 system cache
mkdir /config 0500 root root

mkdir /efs 0771 system system
chown system system /efs
chmod 0771 /efs

.
.
.

custom voId.fstab

## Vold 2.0 Generic fstab
## - San Mehat (san@android.com)
##

#######################
## Regular device mount
##
## Format: dev_mount <label> <mount_point> <part> <sysfs_path1...>
## label - Label for the volume
## mount_point - Where the volume will be mounted
## part - Partition # (1 based), or 'auto' for first usable partition.
## <sysfs_path> - List of sysfs paths to source devices
######################

# sdcard mount for the P1
# internal sdcard
{
ums_path = /sys/devices/platform/usb_mass_storage/lun0/file
discard = disable
asec = disable
}
dev_mount sdcard /mnt/sdcard 1 /devices/platform/s3c-sdhci.0/mmc_host/mmc0

# externel sdcard
{
ums_path = /sys/devices/platform/usb_mass_storage/lun1/file
asec = enable
}
dev_mount sdcard1 /mnt/sdcard_ext auto /devices/platform/s3c-sdhci.2/mmc_host/mmc2
#end line ## keep this line

after rebooting:

- the custom voId.fstab is completely ignored...

- init.rc is changed to custom init.rc

- folders and linkings are correct

but it also links to /sdcard and /sdcard/external_sd

i dont want my external sd-card on /sdcard/external_sd and the internal on /sdcard

is there no way to fix that?