i am not sure if i give you now the right answer for your question!
if you want to have a custom side in a custom map its easy!
you just need the bfbuilder pro!
here is a small tutorial!
1. open bfbuilder pro
2. create a new project with the mapname of the custom map you want to put in the side folder!
3. click on edit and open as example "CW Mission LUA" (or GCW Mission LUA)
4. now search these lines:
ReadDataFile("SIDE\\cis.lvl",
"cis_inf_basic",
"cis_inf_countdooku",
"cis_inf_droideka");
ReadDataFile("SIDE\\rep.lvl",
"rep_inf_basic",
"rep_inf_macewindu",
"rep_inf_jet_trooper");
5. change ReadDataFile("SIDE\\rep.lvl", and ReadDataFile("SIDE\\cis.lvl", to ReadDataFile("dc:SIDE\\rep.lvl", and
ReadDataFile("dc:SIDE\\cis.lvl",
6. do the same with galactic civil war!
7. go back to bfbuilder pro and click on "sides" and then on "import retail side"
8. import "rep", "cis", "all", "imp"
9. close the LUA and munge the project!
10. go to C:\BFBuilder\AddOn and look for the map you munged
11. open it! click on _lvl_pc, then on side!
12. now you copy the custom side you downloaded and put it into the the side folder! (overwrite everything!)
13. now go back to _lvl_pc and open the folder that is called as your ModID!
14. in the folder there should be a .lvl file called as same as your ModID, delete it!
15. go to the custom map you want to have and open it!
16. click on _lvl_pc and open the ModID folder!
17. copy the .lvl file inside the folder and put it into YOUR ModID folder!
18. now copy the map into your battlefront - addon folder and play the game
i hope you understood the tutorial!
maybe i'll give some screenshots later!