Hey everyone
One thing I do know is, you can't upload the .xml file until you register it with Google Base first. When I did my "save as" after clicking the orange RSS button in my eBay store, I chose a filename that would be easy for me to remember (you could do something like "myebaystore.xml"). When you go to the Google Base screen to register it, make sure you type it exactly as "myebaystore.xml"! I just did those exact steps and my feed show up great! And it didn't overwrite my other bulk upload file (the one I use for my web store) like I thought it would, it just added more items. Yay!!!