Add registration fields to Membership

Is there a way to add additional required fields on the registration form in Membership? I am not using buddypress, and don't really want to install it to get this functionality.

There are a number of plugins that allow me to add registration fields to the default WP registration form, but i don't know how to do this for Membership form.

If that isn't possible with Membership (it should be), then is there a way to use the default WP registration form (which i CAN add fields to) instead of the Membership registration form?