DivingDuck, thank you for showing me where the JSON files are on Windows. It works.
Smithy, thank you for your explaination and help. IT WORKS.
I did try to write off the Disallowed Area in Ultiamker2_plus file first, but it didnt work. I then edit the Ultimaker2.def files instead, writing off the Disallowed Area and change the built volume of X,Y and Z.
Now my models in Cura can fit into my built volume and slice without problem, while retaining the settings of Ultimakr2+ I had used.
Thank you