Hi,
I'm experienced in eBay and Rakuten programs. I would like to tell you one thing, we can't put new products immediately into rakuten automatically, as they need to approve the listings , we need to send them the feed by email then only they will authorie to upload. After that we can manage inventory and load the csv's once they approved for the first time.
I will provide my Rakuten store details in PM when you communicate with, i'm able to import all your eBay products into rakuten for the first time and then i will give a script to update the stock updates into rakuten.
Please chat with me for more details :)
Thank you,
Karthik:)