I successfully enabled the OEM brake controller tonight using forscan. I bought ($30) the above ODB2 ELM Tool from Amazon and it showed up today. It was in a bag with card that had the url to get the drivers. I downloaded the vcp drivers and installed them on a laptop. I also downloaded and licensed forscan (free).
I referened the following spreadsheets for the codes needed.
F150 sheet. (had the code for the trailer break module)
2015 Expedition sheet (does not mention the trailer brake module)
Looks like the ones you want to change are
Trailer Brake Control Module enabled IPC 720-07-01 xxxx x*xx xxxx if your as-built is 0, use 8. if your as-built is 6, use E
Trailer Brake Controller Gain Setting enabled IPC 720-04-01 xx4x xxxx xxxx
I did this and sure enough, pressing the module now puts the gain +/- up on the dash. I also have the option for electronic/surge or electronic/hydrolic on the trailer options.