Anyone know how to use OnlineGameSearch?

When I query servers advertising on Steam I use:

SearchSetting = new class'MyOnlineSearchSettings';
SearchSetting.bIsLanQuery = false;
SearchSetting.MaxSearchResults = 1000;
gameInterface.FindOnlineGames(class'UIInteraction'.static.GetPlayerControllerId(0), SearchSetting);

However I have no clue of how to add search filters beyond the existing params listed in OnlineGameSearch.uc.

I have custom game settings that I advertise with a class that extends UDKGameSettingsCommon. And in my OnlineGameSearch I have a GameSettingsClass var that references my settings class.

I just don’t know how to build a query that takes my custom fields into account.

Does anyone have any knowledge of using this? I can’t find any documentation.