Modified Client through Kongregate

Been trying to figure out how to make it work but I have little experience messing with this stuff. Is it possible that there is somewhere in the client to add a used ID and secret (Kong's version of password) so that it connects?

bump for my own interest, would like to use the mods on a kong account. I see there are ways to load kong accounts through the projector, but not sure how I could edit the modded clients to use it.

Link your Kongregate account to a normal web account, then you can simply log in with the web account's credentials to play on the Kong account. To do this, open RotMG in Kongregate as usual, and click the Account button from the main screen. It should be self explanatory from there.
Once you're linked up, open whatever client you prefer, and use the account that you linked to Kong.