Default Bootloop after downgrade from 4.3 to 4.2.2

Hi,

I'm a bit stuck here with my plan.
I updated to 4.3 via OTA because I read here that someone managed to keep his root with the OTA survival mode.
In my excitement I also tried it and of course it didn't work ... would have been too easy right ?

Now I created an 4.3 pre-rooted ROM with NUTs guide without problems and made this todo list:

1) Downgrade back to 4.2.2 (10.3.1.A.2.67)
2) Root
3) Install recovery
4) Continue with 4.3 plan...

To me this looks right, but it doesn't work ... I'm already stuck at number 1.
I used this guide here http://forum.xda-developers.com/show....php?t=2240614 and I'm pretty sure there has to be a certain combination with the wipe data/cache/appslog.
I want to keep my data so I unticked it, but it doesn't work, it freezes on bootup at those waves after the XPERIA logo and keeps on looping forever.

Another user got the same issue here http://forum.xda-developers.com/show....php?t=2336980 but it worked for him (as it seems) and he could keep his data.

So is there anything else I can do to keep my data but still go back ?

Regards,
iCEQB