Is there any way to set a manual recording on HR20?

You can, but it might not work.

There has been manual recording bugs for the past few releases.

BTW if I remember correctly the option is under the menu button somewhere.

Fortunately manual recordings do the most important work, record. There are some problems with retaining a set number of manual recordings, so they've taken that option out for the time being, but that is a minor annoyance compared with the history for the HR20...

To set a manual recording, MENU, Help & Settings, Scheduler, manual. Then make the changes you want. (If you start on the channel you want to manually record, it is easier.)

Cheers,
Tom