Direct Usage and Theming

[sianabanana]

I have an MVC app that i use the ThemeDescriptorFilter to succesfully
theme my app.

My app also sends out Emails which i would like to theme. These are
currently being generated by direct usage.

TextWriter writer = new StringWriter();

SparkViewDescriptor descriptor = new
SparkViewDescriptor();
descriptor.AddTemplate(templateFileName);

SparkTemplateBase<T> view =
(SparkTemplateBase<T>)engine.CreateInstance(descriptor);

try
{
view.Model = model;
view.RenderView(writer);
}
finally
{
engine.ReleaseInstance(view);
}

return writer.ToString();

Has anyone used theming with direct usage before?
Can anyone point me in the right direction?