Howto Retrofit TPMS

[KKEVANSKK]

Hi Everyone, 
 
This is my first time posting on here and im not sure if im posting this in the right place. Anyway,
 
I would like to retrofit TPMS into my astra, and i've cheked that i've got the right pins,wires and fuses in the boot. Iv'e got front and rear parking sensors and a aftermarket 13PIN towbar. 
 
My question is when i fit the new loom in the boot will it be possible to fit the factory trailer module and wiring? I understand this will need programing in the BCM to tell it its present and to turn the rear parking sensors off when in reverse with a trailer/caravan attached but i can get this done when the TPMS is programmed. So, does anyone on here know how to do this and what wires go where etc or should i just stick with the aftermarket relays and wiring?
 
At the moment i know i need the following if im going to fit TPMS and the Trailer Module + Wiring :- 
 
13345922 - HARNESS, ASSY., REAR BODY (IDENT 5G9) (FOR PARKING PILOT SYSTEM) (FOR TYRE PRESSURE MONITORING SYSTEM) (FOR REMOVABLE TRAILER COUPLING)
 
13348393 - SENSOR, WITH VALVE (FOR TYRE PRESSURE MONITORING SYSTEM)
 
24455308 - NUT, TYRE VALVE STEM (FOR TYRE PRESSURE MONITORING SYSTEM)
 
13321961 - (Control unit, tyre pressure monitoring system)
 
13586468 - (Trailer/Towbar Module)
 
I've been unable to find a new/used loom online for the rear body to fit the TPMS and Trailer coupling and also the additional wires needed to the 13PIN socket. Anyone no any idea where i can find these on the cheap? It would be ideal if i could get the trailer module and its wiring together.
 
I really would love to do these retrofits,especially the trailer module and wiring as i havent seen anyone else do this before. If the trailer module is impossible to fit i want to fit TPMS what ever happens.
 
Im planning to fit every thing myself and get someone to program every thing. If anyone has any infomation about this and can aid me in anyway it would be much appreciated.