Modify or develop Magento extension to automatically delivery serial keys.

Hi, we have Serial Codes extension from here - [login to view URL] but we need to modify for our stores or build new one from scratch. we need : - send only txt keys - connection to outside database with keys - after receiving payment to send the key from database by item ID using email template - must work with stores view - we have 2 stores/domains on the same Magento panel - re-send option and send new option - history of sent keys in costumer orders - in order grid serial keys status info (sent, waiting, ect) - stop/start extension option - manually send option for some orders - history of sent keys, orders, email in our database (you need to develop small php script for this) security & options: - extension needs to check that received payment sum match order value - customer must be "Payment Verification" - check box on customer info page - on customer view page admin can chose order limit for automatic delivery per day for customer (50-0) - so extension will send max 10 order per day or if 0 admin will do manually - on product view admin will add limit of items per day for one customer - on product view we need to add email template which extension will use to send key (for each store can be different) - on product view admin will add item id from database to connect Magento product with keys database product - orders paid by Paypal need to wait for admin approval (some can be send by extension - flag on customer view) Happy bidding and thank you for your time.