How to set device specification

Hi

I am unable to set Specification attribute (328) in device using API.
Please have a look at my code below and tell me the right way to do it. I am trying to set as text value and it does not work.

var _point = releasePointFolder.NewChild(ObjectKind.Device, ObjectType.ProcessFluidMiscellaneous);
_point.Attributes.SetAttributeValue(AttributeId.Designation, "Inlet1";
_point.Attributes.SetAttributeValue(AttributeId.Specification, "Release point";
_point.Attributes.FindById(AttributeId.Specification).IsFromCatalog = true;
_point.Store();

Thanks & Regards
Pushpendra Kumar