heather mack , now 19 , is set to sign over a ` significant percentage ' of her trust for the care of daughter stella .
mack claimed in february her uncle denied her access to the $ 1.3 million .
prosecutors in indonesia accused mack and boyfriend , 21-year-old tommy schaefer , of murdering sheila von wiese-mack at a luxury bali hotel .
officials say the couple stuffed heather mack 's mother 's body into a suitcase .
prosecutors have not sought the death penalty for mack or schaefer .
stella is currently staying with her mother in the kerobokan prison in bali .