Code:
Public Sub PublishDXF()
    ' Get the DXF translator Add-In.
    Dim DXFAddIn As TranslatorAddIn
    Set DXFAddIn = ThisApplication.ApplicationAddIns.ItemById("{C24E3AC4-122E-11D5-8E91-0010B541CD80}")    'Set a reference to the active document (the document to be published).
    Dim oDocument As Document
    Set oDocument = ThisApplication.ActiveDocument
    Dim oContext As TranslationContext
    Set oContext = ThisApplication.TransientObjects.CreateTranslationContext
    oContext.Type = kFileBrowseIOMechanism
    ' Create a NameValueMap object
    Dim oOptions As NameValueMap
    Set oOptions = ThisApplication.TransientObjects.CreateNameValueMap
    ' Create a DataMedium object
    Dim oDataMedium As DataMedium
    Set oDataMedium = ThisApplication.TransientObjects.CreateDataMedium
    ' Check whether the translator has 'SaveCopyAs' options
    If DXFAddIn.HasSaveCopyAsOptions(oDocument, oContext, oOptions) Then
        Dim strIniFile As String
        strIniFile = "C:\tempDXFOut.ini"
        ' Create the name-value that specifies the ini file to use.
        oOptions.Value("Export_Acad_IniFile") = strIniFile
    End If
    'Set the destination file name
    oDataMedium.FileName = "c:\tempdxfout.dxf"
    'Publish document.
    Call DXFAddIn.SaveCopyAs(oDocument, oContext, oOptions, oDataMedium)
End Sub