Adding data to a Requirement User field

We have a requirement to add the requirement type and requirement ID to a user field. We would like to accomplish this using the workflow and OTA during requirement generation. Below is the code I have right now. I can get the msgbox to popup containing the correct data; however, it is not posting to the database. We are using version 12.01. I've also been making posts here reagrding this: http://community.hpe.com/t5/Requirements-Management/Persisting-the-requirement-ID/td-p/6772074

Sub Req_AfterPost
  'On Error Resume Next
      Set  newReq = TDConnection.ReqFactory.Item(Req_Fields.Field("RQ_REQ_ID").Value)
      msgbox Req_Fields.Field("RQ_TYPE_ID").Value&": "&newReq.ID
      newReq.Field("RQ_USER_12") = Req_Fields.Field("RQ_TYPE_ID").Value&": " &_
       Req_Fields.Field("RQ_REQ_ID").Value

      newReq.Post
      Set newReq = Nothing

  On Error GoTo 0
End Sub