base 64 encode by ebay (ending with **)

I found this and thought it was my bug .. but ..

When I get IEASToken in getUser ebay api request it returns a token with == a the end. It is a base64 encoded string, and have ‘=’ sign at end as expected. But when eBay send notification, there are ‘**’ in place of ‘==’

So in php I register it as base64_encode(base64_decode(IEASToken)) ..