FOUND A SOLUTION!!!!!!!
here are the instructions:
1. download
This Zip File and extract it somewhere. (it contains the files you need)
2. open your FTB install location (it will be shown in the settings tab of the launcher)
3. copy the librarys folder from the zip into that folder (it should ask you to merge it)
4. copy the pack.json file from it to the minecraft folder of the modpack you want to add liteloader to (so for the Direwolf20 pack, it would be: <FTB INSTALL DIR>\Direwolf20_1_6_4\minecraft) you should be prompted to overwrite an existing file
4. if you havent already, select the modpack and select edit at the top, then add your .litemod files.
5. start minecraft! you mods should load!
This is verified working using mumfrey's worldedit CUI mod for 1.6.4 (found here)
you will need to re-copy the pack.json file and your .litemod files if the modpack ever updates or you manually select a different version, so keep a backup of them
NOTE: The link has been updated for packs that are now using Forge 165. If you're still using a mod-pack that uses Forge 153 (i.e. direwolf20 1.0.8 or lower), download this one instead: Forge 153