ok, got help from T. thanks
Everything points to the need to having a device specific branch available.
For 4.3 that would mean cm10.2 that can be ported to Omnirom.
For 4.2.2 stock source I would need to get own sources to 10.1 first, then port the 10.1 to 10.2.
Which for my device is going on for 10.1.
Once ported configurations must be changed, mapped to the 4.3 specifics so everything works.
Not so easy.
I guess proper procedure would be to check if your device has 10.2 support. Then follow if you can find a standard routine to add your device and then do the configurations.