OK, see if this will work for you. Do you have another computer or laptop that you don't use for Flight Sim? If so, you can install the version 1.0.1.1 from the TWVA FLEET, New Arrivals Section on it.
If so, I believe it installs to C:\FS-Products folder. Copy that folder to one of your data drives of your Flight Sim Computer (preferably not the drive with your newer version of kACars installed on it). Then try launching the kACARS.exe from that folder (as administrator) to see if it will let you setup a VA Profile for TWA and use that launch location for the v1.0.1.1 that the TWA site requires.
I was able to do that on my non-FS computer and get it to launch and connect to the TWA site. However, it does not have flight sim on it to test connection to the simulator. I believe it will work, as I think kACARS looks at the registry to tell it where Flight Sim is installed. All of its' settings regarding VA and user profiles are stored in a config file of whatever folder you are running kACARS from.