This is what I posted in the Moldy Crow/Virago thread. I figured it would be useful:
"Oh god... six hours of modding yesterday gave me the answer to adding heroes for the campaign. I'm planning to release a mod, but in the mean time, I will tell you how to do it(as best as I can) and be credited for the finding(since many people are doing it, I might as well band wagon along).
Alright, every campaign in the campaigns singleplayer xml has 2 lines like this (or similar):
<Rebel_Story_Name>Story_Plots_Sandbox_35_Rebel.xml</Rebel_Story_Name>
<Empire_Story_Name>Story_Plots_Empire_AI_Heroes.xml</Empire_Story_Name>
Those lines tell you where the starting heroes for that campaign are(the file Story,etc). Do a search through your xmls to find the appropiate file; depending on who you want to play as, or if you just want to add both, then you'll have to edit both of those files.
Take a look at this:
<!-- Spawn Time Era 4 Heroes -->
<Event Name="Empire_AI_Heroes_09">
<Event_Type>STORY_TECH_LEVEL</Event_Type>
<Event_Param1>4</Event_Param1>
</Event>
<Event Name="Empire_AI_Heroes_10">
<Event_Type>STORY_TRIGGER</Event_Type>
<Reward_Type>SPAWN_HERO</Reward_Type>
<Reward_Param1>Darth_Team</Reward_Param1>
<Reward_Param2>Naboo</Reward_Param2>
<Prereq>Empire_AI_Heroes_09</Prereq>
</Event>
<Event Name="Empire_AI_Heroes_11">
<Event_Type>STORY_TRIGGER</Event_Type>
<Reward_Type>SPAWN_HERO</Reward_Type>
<Reward_Param1>Mara_Jade_Team</Reward_Param1>
<Reward_Param2>Naboo</Reward_Param2>
<Prereq>Empire_AI_Heroes_09</Prereq>
</Event>
This code is part of one of the campaign hero story starts. I added the tag at the end after setting mara jade's ranking in Herocompanies to:
<Ranking_In_Category> 3 </Ranking_In_Category>(was five, which gave CTD)
Once you get to actually adding the heroes to the story files, make sure they go under the right timeline.
Thats pretty much it. If if doesn't work, I'll try to post a mod (there are a lot of other things which cause CTD if after you enable the heroes for battle use). You have permission(as if anyone cares anyway) to use the info above in your own mods, but I would appreciate some recognition in those readme's (Time is precious, and me wasting it for you guys and myself because I have nothing better to do right now deserves some credit, right?)"
Happy Modding ;)