i faced a similar issue.. to resolve it, in the create multiple case option, i had to set Source page parameter name as some page... now when the cases get created for each page list i set the values from that Source page to some pproperty in my child case...
Is your child case type showing up correctly when you try to perform the below step. If so it confirms that you have the parent - child relationship configured correctly in your application and only then you can attempt the configurations I have mentioned in my earlier post.
"4. Case type >>> Choose the child case type from the drop down"
Also what is the class of the pagelist property that you have defined in the class (CTSHy-OnlineGr-Work-OrderGrocery) ?