Leichi - dream world
salac - not been releesed i beleive has been an event item on mew and jirachi in the past though
Petaya - also never beeen released but was an event berry for jirachi deoxys and pikachu in the past though
Custap - also never been releesed but have been event items for regigigas and entei in the past
all these items are can be found useing action replay or you can get any item on pokemon online but that is an online game which can not connect with the ds
edit : also the petya berry is found on the game freek guys simisear simisage and simipour so maybe a move like theif or eat it with bug bite
