Any options to work around this?
The inability to unset a jetway it's just an editor (intentional) limitation, since we never anticipated a case were users would want to have front stairs on a parking that has a jetway, but the program itself will recognize a disabled jetway through an airport .INI file.
So, you can go to the %APPDATA%\Virtuali\GSX folder, and edit the .INI file for the scenery which should be there, if you made a least a modifcation to it, and change the lines that says
hasjetway = 1
into
hasjetway = 0
For each parking that has a jetway that you want to disable, in order to get front stairs.
Note that, in order for the parking to appear there, you must at least a change to it with the GSX editor, regardless how small it is, otherwise the parking won't be listed in the .INI file. You might change something like the maximum wingspan, for example, setting it to a good value for the typical largest airplane that can go there. If you do it by selecting (CTRL+Click) multiple parkings at time, all the ones that you need to disable the jetway, it should be very quick.
Once you have all the parkings listed in the .INI file, should be easy to change all their "hasjetway" commands from 1 to 0.
Then, after saving the modified .INI file, Restart Couatl from the menu to see your changes, and the editor will show "No Jetway".