I checked on this link Create a User-Defined Object and Set Its Object Identification Properties, but I think it's only for Windows Class Object, I am unable to create a Web Object (I need to create a new Web Element using scripting)
I always failed on this step below:
Set UserDefObj = qtApp.Options.ObjectIdentification("WinListView").CreateUserDefinedObject("MyCustomListView")
I modified the "WinListView" to "WebElement"
Set UserDefObj = qtApp.Options.ObjectIdentification("WebElement").CreateUserDefinedObject("MyCustomWebElement")
The operation attempted is not supported. (Exception from HRESULT: 0x80004021)