Unable to convert the extended DAC Fields in the Related Items Tab in Stock Items IN202500 screen classic to Modern UI

We are trying to  Extended INRelatedInventory DAC Fields in the Releated Items Tab Grid section classic to Modern UI .DAC has 2 extended fields need to display it in the modern UI 
classic UI screen shot
 

Tried with below code, but unable to see fields in Modern UI
 

import { PXFieldState, PXFieldOptions, columnConfig } from "client-controls";

import { IN202500 } from "../IN202500";
import { ReleatedItemsTabBase } from "../../common/related-items/tab-related-items/tab-related-items";

export interface RelatedItems_customfields extends IN202500, ReleatedItemsTabBase { }
export class RelatedItems_customfields extends ReleatedItemsTabBase {
    @columnConfig({ width: 100 }) UsrNAWSurchargeSO: PXFieldState;
    @columnConfig({ width: 100 }) UsrNAWSurchargePO: PXFieldState;
}