there is no entry in available column list when trying to customize "affected objects" table view

Version: Windchill 12.1

Use Case: there is no entry in available column list for soft type attribute when trying to customize "affected objects" table view

Description:

Create soft type attribute of type "Affected Activity Data".

In Affected Object Table of New Activity there is a OOTB disposition named "Finished", "Work-In-Progress", "Inventory". (These are attributes of type  "Affected Activity Data" only).

Instead of OOTB ones I want my soft type to show there. 

But while customizing table view I cant see the entry of these soft types in available column.

How do I add these attributes to the table..?