Enabling Personal Hotspot feature
Tetherme is an app you can purchase and install on a jailbroken device that will attempt to enable the iOS personal hotspot feature on devices and with carriers that don't support it.

Reports are mixed, some user indicating it doesn't work with their particular configuration, others reporting that some carriers detect this usage and disconnect when the personal hotspot is active.

While you are interested in using the iOS personal hotspot, chances are good that the more reliable method is to use a third party utility.

However, if you must use the iOS personal hotspot feature, tetherme seems to be only available option right now.