Adding an LOV to the ERROR_CODE field in form CSXSRISR (Service Request form)

Not sure if this the right community for this but I'll start here.

We are implementing the Fileld Service module and would like to put an LOV onthe ERROR_CODE field in the Workbench Tab on the Service Request form. 

The drop down would be the items (part numbers) from the MTL_SYSTEM_ITEMS_B table.

Looked at the Custom Library option and trying to user the form personalization but not having a lot of luck.

Is there a way to assign an LOV for this field?