Picking up stitches on Purl side

I am knitting a childs sweater in reverse stockinette stitch so the right side is the purl side. The pattern calls for me to pick up stitches at the neckline when I am done but I am not sure how to pick up stitches on the purl side. If I use the knit side (WS) then there will be a ridge on my purl side (RS). Any suggestions would be welcome! :thinking:

I would put the needle in through the bump of the purl, since that would be where the yarn would come through if you did it on a knit side. Does that make sense?

I think this makes sense but not sure. Has anybody else ever tried to pick up stitches on the purl side? Maybe this pattern is not giving me good instructions but it appears that is the only way to complete the sweater. I cannot find any examples of this in any of my knitting books. I may have to wing it I guess.
Thanks for your help Ingrid!