Customizing Loading Dialog based on map being loaded

[HitmanTheMad]

Okay, so I know how to make a custom "loading map" dialog. I can open up Source Engine.gcf and find resource/LoadingDialogVac.res and edit it to resize and create image panels (a lot like the Zombie Master mod did). That's fairly simple. Result? Images and text showing up while I load a map. Cool.

But what I really want to do is be able to swap out images for that panel based on the map that's currently being loaded - much like how Insurgency does theirs, with the specific map objectives and even some text thrown in for good measure, but always specific to the next level. I know how to edit the HUD and add images and other various controls to HUD elements and panels, so I imagine it's not hard - I just need to find a way to access it.

There doesn't seem to be anything in the SDK for controlling this, as I can't find any dialogs or bits of code that would seem to have any functionality over this aspect of the game. But since Insurgency did it, there must be a way.

Does anyone have a clue as to how to go about doing this?