How to update a field as "NULL" using FBDI Template or Configuration Package?

Summary

How to update a field as "NULL" using FBDI Template or Configuration Package?

Content

There are many configurations files that may have either NULL or non-null values. FBDI Templates and configuration package provides option to update the fields.

However we are unable to make a field NULL which has a value, using either FBDI Template or Configuration Package.

Example: 

Configuration Package: Asset_Category_and_Book_Template

If we want to remove the existing group asset number from an asset category, we are unable to achieve it through Configuration Package. While we can do it through User Interface.

FBDI Template: FixedAssetMassAdjustmentsImportTemplate