Problem about returning product and refunding money to customer in POS component

[hoandv]

Hi everybody
I have just a problem about returning product and refunding money to
customer in POS component of OFBiz.
I have created an order which contains the items with negative quantity.
Total due is also negative number. When I pressed "pay"  and "finish"
buttons, I went into order component and I noticed that  the quantity of
items is negative number but ATP and QOH of  those  products  still didn't
increase in facility

I want the ATP and QOH of those products are went up.  Please help me solve
this problem.

Thanks!