Convert Unit Icons to Bif and LBM files

[Belisario]

When I convert a new unit icon to Bif (with Bif Reader) and LBM (with Ultimate Paint) I have some problems. Seemingly the new Bif is correct but in the game it appears with some ugly black dots. If I use the Dragon MTW Editor to obtain the new bif the result is worse because the colour palette results altered.
I’m able to convert the unit icon to LBM using Ultimate Paint, however in the game the green/purple transparent colours appear instead of the faction colours.

Some help, please