Importing kits:
-If you want to replace the ones you already have in the game just import the textures in rx3 files (use Creation Master, even the previous year one will handle the job).
-If you want to add a completely new kit just open the database in dbm12, search for teamkits table, copy one record and assign it to your team, save changes. Then open Creation Master and do the same procedure as in the first instruction.
Regenerating:
-Basically use i68regenerator but if for some reason don't work on your computer try FHL-BH-Editor. All you have to do there is open the needed data file (kits are in data3), find and untick your kit ID (should be the same as the kit you want to replace) and save. The results are now visible ingame.