Hi Amit,
Have you already implemented a custom EmailSimpleTemplateFormatter? The reason I say that is that you'll likely need some functions to loop through the itemized split items as the htm file does not make a call to that level.
I would think you'd want a conditional function to determine if there are itemized items (i.e. @@ifdef=hasItemizations@@ //Some HTML calls @@endifdef@@). Within that condition, you'd need to get the details, and you may need some functions there if dotted notation is too simplistic.