Multiple product keys

Hello,

I'm in the process of integrating LimeLM and TurboActive into my application. I would like to achieve the following:

1. Users register on my website with an email address.2. An email is sent to the user with a confirmation link.3. When the confirmation link is clicked the user gains access to the download page.4. The user downloads and installs the software.5. Once installed a 7 day trial is started.6. Once the trial expires the user must purchase a 6 month license at $xx.7. Subsequent 6 month licenses are priced at $yy (A Discount is offered to loyal customers)

I do not plan to use the "Unverified" trials, my plan is to use Product keys and feature values. My feature values will be

"status" - Integer Type 0 = Trial 1 = 1st 6 month license 2 = Subsequent license

"expiry_date" - Date / Time Type

At step 3, when the email address is confirmed, I generate a Product Key with the status set to zero and the expiry_date set 7 days in the future. The product key is then emailed to the customer.

Here's my problem: If the user de-activates the trial license and registers again using a different email address they receive a new product key and a new 7 day trial. The new product key can be entered and a perpetual trial license can be obtained, you just need a new email address every 7 days.

Any advice would be much appreciated.