My DAC is as follows:

[PXSearchable(
    PX.Objects.SM.SearchCategory.AP, // Choose the appropriate category.
    "Device: {0} ({1})", // Main title format for the search result
    new Type[] { typeof(PseudoNames.ipiNumber), typeof(PseudoNames.pseudoID) }, // Fields for the main search
    new Type[] { typeof(PseudoNames.pseudoName), typeof(PseudoNames.ipiNumber), typeof(PseudoNames.pseudoID) }, // Additional searchable fields
    Line1Format = "{0}",
    Line1Fields = new Type[] { typeof(PseudoNames.ipiNumber) },
    Line2Format = "{0}",
    Line2Fields = new Type[] { typeof(PseudoNames.pseudoName) }
)]
[PXNote]
public virtual Guid? NoteID { get; set; }
public abstract class noteID : PX.Data.BQL.BqlGuid.Field<noteID> { }