How to Make XDocument keep new line in attributes like XmlDocument does?

I am using XDocument and LINQ with great ease and comfort, but

one problem arises:

XDocument removes new lines inside attribute when you try to output back the xml.

XmlDocument on the other hand, keeps the new line.

static void Main(string[] args)
{
    string res;
    string str = "<element attrib='Some text \n with new line'/>";

    XDocument xDoc = XDocument.Parse(str);
    res = xDoc.ToString();
    //res dose not containe the new line.

    XmlDocument xmlDoc = new XmlDocument();
    xmlDoc.LoadXml(str);
    res = xmlDoc.OuterXml;
    //res contains a new line char, that i can replace to something more nice like /r.
    res = res.Replace("&#xA;", Environment.NewLine);
}

I have a lot of code already written with XDocument, and don't want to rewrite it using XmlDocument. How can I get XDocument to behave XmlDocument it this manner?