Oh, you'll need to set the account name query field in the data connection and run the connection. Here's a copy with those rules added to form load for you. However - I just checked an InfoPath Forms Services form on my SharePoint Online tenant, and I get an error even trying to use this web service. So, there is a good chance this won't work. You may want to look into using the SharePoint User Information list instead.
Hilary Stoupa
