In order for the Mag 254 set top box to work correctly and provide a scrub bar for seek and rewind functions during a live event you must add the following to the dvr properties "custom properties" section.
it took several weeks to figure out that this was required and we almost gave up on the Mag 254. if anyone needs a great IP STB Mag is the way to go, Very Stable.

PATH : /Root/Application/HTTPStreamer
NAME: cupertinoDVRPlaylistType
TYPE: String

this will create a playlist that includes the playlist type tag as shown below thus triggering the STB to provide the HLS functionality