Modifying an Autocom headset to plug a normal 3.5mm device in

Hi all,

Does anyone know if it’s possible to modify the headphones of an autocom headset to just plug a 3.5mm device in ?

I want to basically connect one of these:
so that I can have my tomtom give me instructions in my helmet.

I know it’ll wreck the headset, but I don’t even have the autocom unit fitted to the new bike anymore.