Do you have a registered amazon developer account and have access to not only your merchant id, but also your secret key & access key? You do not need to provide the details to us, we just need to know if you have access to them as some people who have access to MWS don't have access to the secret & access key. If you do have access to the Secret & Access Key (under view your credentials), please create a support ticket so that we can ask the developers to enable the key fields for you. If you do not have access to those, then you'll have to go on our waiting list to be notified when we have more slots available to share access - and you'd have to use sku grid for email notifications and/or use the filters on the grid and make manual changes to your listings on amazon.