Hello Olav Birkeland:
The support for K22FN256 is available, but you have to install the Service Pack for K22F/KV31F.
Go to Help -> Install New software, in Work with select "Freescale KDS Update Site" and install the one called "Processor Expert Support for Kinetis K22F/KV31F @120/100 MHz Service Pack". See below:

With this you have Processor Expert support for K22FN256 and other variants of K22.
Regards!,
Jorge Gonzalez
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