How does one face the Kaaba when praying inside the Hateem (Hijr) of Isma'il?

Naming the Hatim as the Stone of Isma'il is not legislated (not Sharia-compliant). The Hatim is a part of the House (Kaaba), but not all of it belongs to the Kaaba; only about six cubits of it do. Whoever prays inside the Hatim must face the Kaaba. If one prays facing other than the Kaaba, their prayer is invalid, because facing a part of the Kaaba is a condition for the validity of prayer therein. The practice of Muslims has been to face the wall of the Kaaba for those who pray inside the Hatim.