HSExtSave v1.0.1  

//HSExtSave plugin

public delegate void ExtSaveCharReadHandler(CharFile charFile, XmlNode node);
public delegate void ExtSaveCharWriteHandler(CharFile charFile, XmlTextWriter writer);
public delegate void ExtSaveSceneReadHandler(string path, XmlNode node);
public delegate void ExtSaveSceneWriteHandler(string path, XmlTextWriter writer);
public delegate void ExtSaveClothesReadHandler(CharFileInfoClothes clothesInfo, XmlNode node);
public delegate void ExtSaveClothesWriteHandler(CharFileInfoClothes clothesInfo, XmlTextWriter writer);

/// <summary>
/// Used to register a handler.
/// </summary>
/// <param name="name">Name of the handler: it must be unique and without special characters.</param>
/// <param name="onCharRead">Callback that will be called when the plugin reads a character card.</param>
/// <param name="onCharWrite">Callback that will be called when the plugin saves a character card.</param>
/// <param name="onSceneLoad">Callback that will be called when the plugin reads a scene card.</param>
/// <param name="onSceneImport">Callback that will be called when the plugin reads a scene card (import).</param>
/// <param name="onSceneWrite">Callback that will be called when the plugin saves a scene card.</param>
/// <returns>true if the operation was successful, otherwise false</returns>
public static bool RegisterHandler(string name, ExtSaveCharReadHandler onCharRead, ExtSaveCharWriteHandler onCharWrite, ExtSaveSceneReadHandler onSceneLoad, ExtSaveSceneReadHandler onSceneImport, ExtSaveSceneWriteHandler onSceneWrite, ExtSaveClothesReadHandler onClothesRead, ExtSaveClothesWriteHandler onClothesWrite)

//Your plugin

public void OnApplicationStart()
{
    HSExtSave.HSExtSave.RegisterHandler("theNameOfYourModForExample", null, null, this.OnSceneLoad, this.OnSceneImport, this.OnSceneSave, null, null);
}

private void OnSceneLoad(string path, XmlNode node)
{
    //Stuff
}

private void OnSceneImport(string path, XmlNode node)
{
    //Stuff
}

private void OnSceneSave(string path, XmlTextWriter writer)
{
    //Even more stuff
}