USING EBAY API for updating tracking numbers automatically

Hello everybody , I have a store on ebay that uses PayPal IPN (instant payment notifications - with the IPN help I am able to use my customers payment and use their data in order to create their orders on excel using a software that a freelancer has developed to me. the software inport data from the Paypal and put it organized on the excel file for I wont have to make each order of a customer step by step , time after time.. WHAT I WANT TO BE DONE: after a customer has bought an item from me on ebay. I contact my supplier and gives him the relevant data (name,address,quantity etc) 2 days later , I get the order tracking number directly to my mail - I want to develope a software that will automatically update the tracking number to my customers on ebay. this can happen in two ways : - software can take tracking number and find a way how to use paypal API (access from third party) and update the data. - software can use ebay API to upload tracking number. Hint how to make this work : The freelancer needs modify/configure/create a software that should take the buyer's ID (you can access this data from the IPN of paypal that is already configured !!!) - take the buyer's ID and look it up on the ebay-customers list (Using API option that ebay provides) - and paste the tracking number (that is provided in my personal email) into the correct buyer. This is really an easy task , but please guys - Do not bid if you did not understand a word you have just read. Thanks ! :) Go Go Go ..!!!