There is no need to change any .php files. You can simply follow this link – https://docs.woothemes.com/document/woocommerce-rest-api/
to enable the API. Just use a UI based configuration.
btw, I have sent you a pm as well. Let’s connect at [email protected]
Hi Michael,
There are few options for multi-channel distribution such as Channel Advisors (http://www.channeladvisor.com) that helps you connect to stores like ebay, amazon and several other. I am not sure if they integrate with storefronts (Magento/Shopify etc). They are few other alternatives that you can look into. Here’s a Quora post that discusses few other alternatives to Channeladvisor.
Don’t mean to be salesy but I am part of an e-com workflow automation platform – Core (www.corehq.io). Our platform has a pre-built Magento integration and we are in the process of adding ebay. If this is of interest, please feel free to drop us a note at [email protected]