I did this with mine, but made it automatic subscription upon registration – without check-box.
Click on the “Subscription Steps” and then the “General” tab.
Next to the “Subscription on registration” label you have four options from the drop-down:
-No
-Yes, force subscription
-Yes, show option
-Yes, show option already checked.
Either of the last two will show a check-box. Then, you can even choose the text next to the check-box. Just write “want newsletter?” or whatever you want in the option “Check box label”
Hit save.
Ciao,
L
P.S. I’m using the “free” version -which is the newer version of the pro version. Now the “pro” part of the newsletter comes with the premium module additions.