I believe reminder notifications for EOTs (End of Term) is a feature in the works, but it is not currently an s2Member feature.
Customizing the payment process: If you're referring to collecting additional data during the checkout process, this can be done with Pro Forms (which comes with s2Member Pro). Using Pro Forms allows you to create multiple registration/profile fields that can be made required during checkout.
Regarding the invoices: s2Member is a membership plugin and while it has features that allow it to be used like a shopping cart (for example, you can create Buy Now buttons to sell access to a specific Post/Page), it's primary functionality is built around that of providing membership access.
I do not currently know of any WP invoicing plugins that are compatible with s2Member, but if you just want to provide a unique ID for the transaction to your member, the PayPal Subscription ID can be shown to your users using the s2Member S2MEMBER_CURRENT_USER_SUBSCR_ID constant.Statistics: Posted by Raam Dev — January 3rd, 2012, 5:00 pm
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