Solved;
Thanks Mobius, I followed the character cast skill (buff -> bless the body) methods and solved the steps;
If someone want to do something like this, here is the final code as example:
Skill skill = SkillData.getInstance().getSkill(buff[0], buff[1]);
final BuffInfo info = new BuffInfo(_fakePlayer, _fakePlayer, skill);
skill.applyEffectScope(EffectScope.SELF, info, false, true);
_fakePlayer.getEffectList().add(info);
skill.applyEffects(_fakePlayer, _fakePlayer);
OBS:
buff[0] = id of buff (skill id);
buff[1] = level of buff (skill level);
_fakeplayer = my class who extends from L2PcInstance;