The RNAV column simply selects the nearest VOR and gives each turning point its bearing and distance from it. If you want to fly specific VOR radials you'll need to make a note elsewhere I'm afraid.

I'm planning a flight on the ipad, and I'm planning to fly some VOR radials. However, in the pilot's log, it seems that I can't instruct skydemon about which VORs I want to fly on - it picks them for me, and I can't seem to be able to change that. 

Can somebody help?

Thanks, 
/Martin