If you put a Fiddler breakpoint on char/list and account/verify and add <IsSupporter>true</IsSupporter> to the XML response, you can log into the game and try playing. The issue is you will get the following error. I think, Unity client might send some kind of packet informing the server you have logged in from Exalt and the server checks if you have permissions to do so. I am not familiar enough with C# so I couldn't prove my theory.
[IMG]https://user-images.******userconten*****m/42045258/77163431-1ad9ca80-6abf-11ea-810b-5d065af89463.png[/IMG]
P.S. also I am creator of HTTP proxy for rotmg and it seems to be working with Exalt too so I could write a plugin for it.