You normally treat the yo's as a normal stitch. If you're purling all the other stitches, purl the yo; if you're knitting, knit it. You don't knit into the back of it, because that would reduce the size of the eyelet the pattern is making.
"Trust the pattern!"
Time flies like an arrow, but fruit flies like a banana.
Hop aboard while we follow the cloud-covered van of knitting harmony, man!! Woooo!! --Hedgehog
IngridKH on Ravelry