Verify signature after add a document

Hello, I have developed an application with graphometric signature technology.
Now we are testing some functionality and I found that if I open a document with a signature field that has to sign the program correctly indicates that the field is to be signed.
But if I attach a document, as an additional page, and this document has already been signed signature fields, the program no longer detects the field without signing, but considers them all signed.
The code to see if the signature field is signed is the following:

Dim ret As Boolean = False
If (fld.GetValue Is Nothing) Then
Dim value As Obj = fld.GetValue ()
If valore.IsDict () Then
If valore.Find ( “ByteRange”) isnot Nothing Then
ret = True
'Signature field NOT Signed (2)
End If
End If
End If

Return ret

The code to attach new document is the following:

Using in_doc Good PDFDoc (_pathScan)Dim mediabox As Rect = _pdfdoc.GetPage (1) .GetMediaBox ()
Dim itr As PageIterator = in_doc.GetPageIterator ()

While itr.HasNext ()
Dim newPage As Page = itr.Current ()
newPage.SetMediaBox (MediaBox)
_pdfdoc.PagePushBack (newPage)
itr. [Next] ()
End While
End Using

You know how to give an indication?

Any suggestion is greatly appreciated.
Thank you.
Best regards.

The issue appears to be related to the fact that you are not importing the Page from one PDFDoc object to the other.

The proper way to import pages is described in the PDFPage sample.

For example

Dim copy_pages As ArrayList = New ArrayList
Dim itr6 As PageIterator = in_doc6.GetPageIterator()
While itr6.HasNext()
End While

Dim imported_pages As ArrayList = new_doc6.ImportPages(copy_pages)

you can now call PagePushBack on the pages in imported_pages