Planning to upgrade on 4.0 but have 1 question.
 

Hello
I'm planning on upgrading my license to vbulletin 4.0.
My website is actually a product based website on which i'm providing contacts inviter for vbulletin platform websites. You can visit it at www.projectsplanet.org
However i'm willing to have customer section on my website just like vbulletin.com's customer section. When user log in to customer section* he will see options to download different versions of my product (in zip format)* download different updates only (in zip format) and renew/upgrade license etc. (Just like vbulletin.com's customer section).
The thing is i got so many customers (more than 1500 now) and its very very time taking and frustrating to manually email every customer whenever i release any updates. Products like contacts inviter require atleast 2 updates a week.
Well* in my product* every customer is provided with 1 php license file (which is different for every customer.. Just like vbulletin's license file).
Now as far as i can see* vbulletin's product zip/tar is formed dynamically when user clicks download button in customer section (It must be pulling some regular product files and adding 1 license file at runtime and form a zip).
So my requirement is* i'll be creating folders for each customer on my ftp. Every folder will contain only license file for that customer. And outside that* there will be 1 main product files folder. Now at runtime it should grab all main product files and add license file for that logged in customer from his folder on ftp and form a zip for download (the zip is not there after he downloads the product.. but files will be there so next time he clicks download* same procedure will be repeated).
This will make my work very very easy. I just have to upload license files/upgraded files on ftp and customers can download 'em any time they want.
BTW whenever anyone purchases my product* i will be creating customer login account for that user and i'll be emailing him login credentials. Which he can use to download different versions and upgrades from my customer section.

So i would like to know* is there any ready made mod available for this?? or is it already there in vbulletin's package?? or vbulletin CMS can do it or do i have to use any 3rd party scripts for that? (If yes then which).
Also* if it requires custom coding then i would like to know how vbulletin's customer section is coded and is there any specific name for this kind of requirement i should be looking over internet?

Thank you very much in advance.