存储过程取sqlserver的时间，vb客户端返回总是0

Dim rst As Recordset
  Dim cmd As ADODB.Command
  Dim par2 As New ADODB.Parameter
  Set cmd = New ADODB.Command
  cmd.CommandText = "ServerTime"
  cmd.CommandType = adCmdStoredProc
  Set par2 = cmd.CreateParameter("output", adDate, adParamOutput, 20)
  cmd.Parameters.Append par2
  Set cmd.ActiveConnection = g_Cn
  cmd.Execute
  Debug.Print cmd.Parameters("@st")  --应该是这样
  End If