Hi Julius,
You need to reconsider your use case.
How about this?
Try to create just one BO that contains all the information you need.
Root level elements and a node structure.
element AccountID :ID;
element AccountName :Text;
node item [0,n]{
element itemID : ID;
element itemName : Text;
}
Then create an EC using that BO.
Let me know if you have any trouble with this.
Best Regards
Fred