Receiving radio stations on Humax 9200t PVR?

This question is how to tune in to the radio channels on a Humax 9200t PVR. I have just done a rescan on my friend's Humax 9200t PVR as Film4 and ITV4 had dropped off the channels list for some reason. During the scan you can see the TV and radio channels as they are picked up. At the end of the scan it tells you how many TV and how many radio channels have been picked up. However, none of the radio channels are displayed on the Channels List or the Programme Guide. The Programme Guide is headed "TV" so do you have to change to "Radio" somehow? If so, how? On my Humax Freeview HD Recorder there's a button on the remote to toggle between TV and radio but I can't find anything like that on my friend's remote. In case you're wondering, he's never listened to the radio on it before - it was only when I suggested to him that he could record radio programmes that he realised he couldn't tune into them. Any advice would be much appreciated.