Can′t register to a mailing list

Hi!

I have a WooCommerce site, and I want the customers to subscribe to a speciell mailing list called “Newsletter”. I have the checkbox in the register page, but when someone ticks the checkbox, the only thing that happens is that the customer registrers to the list “WordPress users”. I have selected the right mailing list in settings of MailPoet, but it would not work.
I′m using the plugin “MailPoet WooCommerce Add-on” and that works, but it only works in the checkout page, want it in the register page also.
Please help me before it gets too many registrations from people.

/Peter