Serialize object to XML file specified not by path, but by TextAsstet

Hi, I Have som issues with XML serialization. I usually serialize object to XML file like this:

     XmlSerializer serializer = new XmlSerializer (typeof(SomeType));
     XmlWriterSettings setting = new XmlWriterSettings ();
     //..settings (encoding, intent...)
     XmlTextWriter writer = XmlTextWriter.Create (path, setting) as XmlTextWriter;
     serializer.Serialize (writer, object);
     writer.Close ();

But now I want to serialize object to XMLfile. I don't know path to that file, but I have reference on it (TextAsstet). I want something like:

 XmlTextWriter writer = XmlTextWriter.Create (textAsset, setting) as XmlTextWriter);

I tried to use Assetsdatabase.GetAssetPath(textAsset.GetInstanceID()); , but it doesn't work on android.

Is there any way to serialize object to file whose path I don't know, but I have reference to it?