Auto-copy value from material transaction (Misc Receipt) standard field (Item) to a DFF

Summary:

Is there a way to auto-copy value from material transaction (Misc Receipt) standard field (Item) to a DFF? I'm trying to pull the item number, uom and quantity down from the standard fields into custom DFFs. This way I can derive available PO information from these selections.

I have been unable to link the DFFs to standard fields. I've some information on creating triggers, but the Work Order Material Transaction standard object isn't available for me to add a trigger to.

Content (please ensure you mask any confidential information):

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

Code Snippet (add any code snippets that support your topic, if applicable):