I've just tried this with 10.0.0.22 and it seems to be working as long as I set BaseURL as follows
SET OutputLocalEnvironment.Destination.REST.Request.BaseURL = 'http://something.hursley.ibm.com/customerdb/v1';
in a Compute node before the RestAsyncRequest node, and also set the "Compute mode" property to "LocalEnvironment and Message" (which I often forget!).
Hope this helps - might be worth opening a case if it doesn't work for you.