It took me a minute to remember what I meant by that, but here it is.

On page 12 of your manual, right column, it describes how by pressing TV/VIDEO and a number from 0 through 6 you can have it direct-select VIDEO1, VIDEO2, VIDEO3, etc.

While I haven't actually done this, I figure that the recording procedure would be the same as programming the REC+PLAY key, by hitting both keys at once.

Naturally, you're not limited to simply TV inputs: you could use this feature to sneak a few more unrelated signals in the same screen.