GoogleDocs BackUp or document copying between 2 accounts

Question

I'm trying to copy a document from account 1 to account 2.
On account 1 it works this way
Example C# program 
using System;
using System.Collections.Generic;

using System.ComponentModel;

using System.Data;

using System.Drawing;

using System.Linq;

using System.Text;

using System.Windows.Forms;
using Google.GData.Documents;

using Google.GData.Client;

using Google.GData.Extensions;
namespace Copy_document
{

public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}

private DocumentsService ds;

private void button1_Click(object sender, EventArgs e)
{
this.ds = new DocumentsService("doc service name");
this.ds.setUserCredentials("[email protected]", "Password");
this.ds.QueryClientLoginToken();
SpreadsheetQuery query = new Google.GData.Documents.SpreadsheetQuery();
query.Title = "12345";
query.TitleExact = true;
DocumentsFeed feed = this.ds.Query(query);
AtomEntry entry = feed.Entries[0];
entry.Title.Text = "12345BackUp";

var feedUri = new Uri(DocumentsListQuery.documentsBaseUri);
this.ds.Insert(feedUri, entry);
}
}
}
the copy of document is created.


Please, help me to implement copying to another account.


I see the problem is we don't have any initial pasting position on account 2.
+ consider the situation if only that document is modified.


I would appreciate your help.