I want to use the internal mmc (mmc2) as ext3 instead of fat because I can symlink it with setting full attributes.

The predefined file 'mount-mmc' contains

#!/bin/sh
mount -t vfat -o rw,noauto,nodev,nosuid,noatime,nodiratime,utf8,uid =29999,shortname=mixed,dmask=000,fmask=0033 "$1" "$2" > /dev/null

which acts for *both* mmc cards, but I want to leave the external mmc1 as FAT.

After refornatting the mmc2 to ext3 how should I change this script so it mounts mmc2 as ext3 and mmc1 as fat ?

mount -t auto?

There are some flags which work only for vfat and not for ext3, so it won't work.

I did a quick hack that worked:

my /usr/sbin/mmc-mount does that:

That is, it first tries with type vfat and then, if it fails, it goes for auto with some generic flags - notice that since I use my ext3 partition to run some code, I took off the nodev and noexec flags.

OBS.: Test first, please, because I typed this one from memory - I don't have my device right here now.

I did a test with mmc1 by formatting a minisd in ext2 and copying some files onto it, plugging it into the N810 and did not do anything with the mmc-mount file and it worked flawlessly: these files could be read.
Now the mmc2 which I have to backup, reformat and restore.