Easy invitation multisite

Hi, i read other post, and i think that easy invitation codes isn’t build for multisite. I have tried and effectively there is a problem with registering page, in normal site is login/?action=register, in multisite is wp-signup.php

So there is any way to make it works in multisite? or exist any premium version of this plugin (that works under multisite obviously)

There is the possibility to insert which login page is the destination of plugin integration?

thanks