BC E-commerce integrated with Subscription Based Web Application

Question

I am considering using BC for my company's corporate website as well as the online store.  We sell a subscription based web application which will have 3 or more flavors (products) and will need to bill customers on a recurring monthly or annual basis.
For the monthly subscriptions, we want to bill the customer based on the "highwater" mark with regards to user quantity for that given month.  This gives the users the flexibility to add/remove users freely without the fuss of having to contact a sales representative to adjust their account/recurring order. 
I would imagine this would happen one of two ways:
The user signs up creating their account both in our web application and the ecommerce site and is billed for the first time.  In the ensuing months, either: the e-commerce site communicates with our web application to get the high water mark quantity for that billing cycle or
Our web application sends a new order each month to the e-commerce site, including the highwater mark quantity, giving the illusion to the user that it is indeed a recurring order but behind the scenes they are actually individual orders.
Annual subscription customers are a bit more challenging.  We still want the users to have the flexibility to add/remove users with minimal effort. However, since they are being billed on an annual basis, prorating additional users will be necessary.  So if customer who previously purchased 5 licenses, adds 5 more licenses during month 6 of their annual subscription term, we would need the e-commerce solution to bill them once immediately for the 50% prorated 5 licenses, then bill them 6 month's later for the total 10 license subscription renewal.
At a bit of higher level, we would prefer the customer to manage all their billing/account info within our web application rather than going to an external store to do so.
One other caveat, we would prefer not to store credit card info on our site.  Preferably that would be stored in our payment gateway (Auth.net).  This may or may not affect the workflows described above.
My Questions:
Can the BC e-commerce solution support the workflows above?If so, is there any documentation/resources available to research this further?
Are there any BC customers that currently do something similar?  If so, who and how similar?

Answer 1

Hi Greg,
From what you have described it seems to me that you need some complex server side logic which BC doesn't allow. In any case you'd have to develop an app that communicates between BC and that other application through our API, which will control the orders as per your requirement. In particular, there's no easy way for end user to control their recurring monthly or annual subscription, there's no way to apply immediate discounts according to earlier purchases that will satisfy this requirement "if customer who previously purchased 5 licenses, adds 5 more licenses during month 6 of their annual subscription term, we would need the e-commerce solution to bill them once immediately for the 50% prorated 5 licenses, then bill them 6 month's later for the total 10 license subscription renewal", you can't build in this functionality into BC " the e-commerce site communicates with our web application to get the high water mark quantity for that billing cycle" and there are few more things there which suggest to me that you need something custom.
Cheers,
-mario