You'd probably be best off with the backwards loop cast on, (seen here
) for those three stitches.
You're adding these three stitches in the centre of your work to make room for the base of the 'V'.
So, basically, you'll knit up so far: vvvvv and then cast on three stitches: eee before carrying on to the end of the row: vvvvv
Does that help?