Well I followed @Gerwil's suggestion. And unfortunately I'm back to being "comma". All the entries in the customization menu are blank. I'll probably let this rest for now, unless someone comes up with a brilliant solution. The .cfg: 

[FLTSIM.0]
Title="Cessna 414A N356II GTN750"
Model="\..\..\flysimware_Cessna_414AW\model.GTN750"
Panel="\..\..\flysimware_Cessna_414AW\panel.GTN750"
Sound="\..\..\flysimware_Cessna_414AW\sound"
Texture="N356II"
KB_Checklists=""
KB_Reference=""
description=""
wip_indicator=0
ui_manufacturer="Cessna"
ui_type="414AW"
ui_variation="N356II GTN750"
ui_typerole="Twin Engine Prop"
ui_createdby="Flysimware"
ui_thumbnailfile=""
ui_certified_ceiling=14600
ui_max_range=920
ui_autonomy=6
ui_fuel_burn_rate=13.5
atc_id=","
icao_airline=","
atc_id_enable=1
atc_airline="Cessna"
atc_flight_number="N356II"
atc_heavy=0
atc_id_color="0x00000000"
atc_id_font=""
isAirTraffic=0
isUserSelectable=1
isFlyable=1
canBeUsedByAITraffic=1
Effects=""
atc_parking_types="RAMP"
atc_parking_codes=""

37 minutes ago, Cpt_Piett said:

And unfortunately I'm back to being "comma".

Best to try without the EU ATC mod. I don't currently use it, but it may well be incompatible with the latest SU. Or the current SU10 beta if you're using that. There is a thread on the official forum by Nijntje about the EU phraseology mod, maybe that will give some insight.

Guys, I figured it out. The liveries for the 414 comes in 4 different versions depending on the avionics.