Add field options to a panel without datasource?

Hi, I am developing a plugin without datasource. Indeed the plugin make ajax request itself and gets its data. I need this behavior because my plugin is interactive and based on user selection it should show different data from server. Now I want to use the field options in showing data but unfortunately because I do not have any datasource and so any input dataframe the field options is empty in override panel . How can I set the field options manually for my panel to see them in override panel.