I really don't like to spoonfeed people, but since I already have the code:
18666,CD_In_Mouth,CD In Mouth,4,20,,200,,0,,0,0xFFFFFFFE,63,2,1,,20,0,815,{ autobonus "{ bonus3 bAutoSpell,8013,5,40; bonus3 bAutoSpell,8013,4,40; bonus3 bAutoSpell,8013,3,40; bonus3 bAutoSpell,8013,2,40; bonus3 bAutoSpell,8013,1,40; bonus3 bAutoSpell,13,1,10; bonus3 bAutoSpell,13,2,10; bonus3 bAutoSpell,13,3,10; bonus3 bAutoSpell,13,4,10; bonus3 bAutoSpell,13,1,10; }",60,5000,0,"{ specialeffect2 EF_POTION_BERSERK; }"; },{},{}
Notes:
Skill ID 8013 = Caprice; 13 = Soul Strike. Autobonus doesn't support skill names since they (skill names) break the quotation ("") marks.
Caprice randomly casts FB, LB, CB and ES. I gave it a 4% chance of autocasting so as if each bolt is casted at a 1% rate.
Edit: Should have been posted at the requests section?