Do you really need SoD to run EET?

HI,
I'm just wondering if there is a version of EET that doesn't require the purchase of Siege of Dragonspear? Or is there a workaround you can use to avoid it? I'm not asking because I'm tight, but I just don't think SoD is for me.
I'm also not sure how the stories follow each other. In the old BGT after killing Sarevok you returned to Duke Belt and then got transported via a cutscene to BG2. In EET where does SoD fit into this?
Any advice welcome,
Thanks.