First of all, thank you for this module, it's exactly what I need! THANK YOU!
The module is working like a charm but i ran into a little issue. When a registered user, who has no subscription yet, places an order and ticks the subscription check mark - he will not get an e-mail with a confirmation link. Although my newsletter is set up with Double Opt In. Now I'm not quite sure if this issue is caused by your module or if it has its origin on the simplenews end.
You might want to check out my site: www.acewell.de - since I'm using a review page u can click through until there.