I would like add a background to a PDF File using excel vba code, Please help as I cannot find any alternative other that watermarking API

[VBA]Function WatermarkPDF(Base_PDF As String, WatermarkPDF_AX As String)
Dim bolResult As Boolean
Dim pdfDoc1 As AcroPDDoc
Dim jsObj As Object

Set pdfDoc1 = CreateObject("AcroExch.PDDoc")

If pdfDoc1.Open(Base_PDF) Then
Set jsObj = pdfDoc1.GetJSObject
'jsObj.addWatermarkFromFile WatermarkPDF_AX ', bOnTop:=False
jsObj.addWatermarkFromFile WatermarkPDF_AX, 0, 0, 0, False, True, True, 0, 0, 0, 0, False, 1, False, 0, 1
End If

pdfDoc1.Save 1, Base_PDF

pdfDoc1.Close

Set jsObj = Nothing
Set pdfDoc1 = Nothing

End Function[/VBA]