I asked the friend who gave me the pattern, and she said she opened out the back seam of the foot and sewed the elastic directly onto the ankle without a casing. But just opening that part still doesn't leave me enough room to work. If I take the foot off and do it that way, then the bottom of the leg is too wide. I just can't figure it out.
Too bad my friend lives in Pennsylvania or I'd have her show me. One Christmas, she made roughly 25 sets of red jammies as Christmas presents for all the kids in her church. It was amazing. Her two boys and her husband helped, too!
Please visit Shereen at Waiting for Him for more crafty deliciousness.
PS...I actually cut the feet of the lavendar PJs I was making, the casing/elastic was so messed up. But I figure a baby can wear it over lighter PJs...like a blanket she can't throw off.