Thuraya XT Lite earphones

I purchased my satphone mainly for emergency comms and didn't buy an earpiece. However, experience has shown that connection can be a bit flaky hand holding the phone and others have reported that using an earpiece is much more reliable. If you were trying to follow instructions while holding the phone it would be very difficult. Consequently, I decided it would be a good idea to buy earphones for an upcoming very remote trip. Unfortunately, earphones for version 1 of the phone are no longer available, later versions use 3.5mm smartphone headsets. Has anyone used a 2.5->3.5mm adaptor or can tell me the Thuraya 2.5mm plug configuration, TRRS, TRS? There's a lot of info about jack wiring on the net, e.g. details of TRRS (tip, ring,ring, shaft) configuration for the two standards OMPT (l,r, mic,gnd) and CTIA (l,r,gnd,mic). Can't find anything about stereo versus mono. Perhaps Thuraya uses the TRS plug and is wired audio, gnd,mic or audio,mic,gnd, I can't find out if this is even done. I am capable of making my own adaptor if I only knew, otherwise suck it and see appears the only way to go, any information would be gratefully received. I have emailed satphonesales, but they have no information other than to say that they won't be getting any more version 1 earphones.