Page customization using EL expression

Summary:

Disable the “Void Button” under “Action Menu” Using "“EL expressions”

Content (please ensure you mask any confidential information):

We have a requirement to disable the “Void Button” under “Action Menu”, we have explored the chances of modification by creating a sandbox.
But in the “EL expressions” using which we can disable the void button, “DFF” fields are not appearing in the binding parameter drop down list. We have defined about 10+ DFF based on AP_CHECK_ALL table.
Only the seeded fields are visible. Please let us know how we can fulfil this requirement.

Version (include the version you are using, if applicable):