Add Related Svc. Doc Type and Nbr to mobile app Expense Receipt

I am trying to add the following two fields to the Expense receipt on the mobile app

update screen EP301020 {
  update container "ClaimDetails" {
        add field "DetailsFieldServiceDetails#RelatedSvcDocType" {
          placeafter field "DetailsFinancialDetailsExpenseReceipt#Location"
          pickerType = Searchable
          }
        add field "DetailsFieldServiceDetails#RelatedSvcDocNbr" {
          placeafter field "DetailsFieldServiceDetails#RelatedSvcDocType"
          pickerType = Searchable
          }
   }   
}

The fields appear on the screen but when i select a Service or Appointment document it throws an error. I suspect it is because the field is a NoteID but it is trying to save the Order Reference.