I am having this same issue. I setup the servers as described in http://www.howtoforge.com/multiserve...th-ispconfig-3
I skipped the mail server, but that should not effect this problem. The system seems to be creating the databases on the remote box, but it is not allowing access to the databases from the database users. I have given access to root from the box, and I can connect remotely.
Do I need to create the user with access to that box all the time?
I got it fixed. I had to manually edit the config.inc.php file because it was not recognizing the changes. The only issue now is that I have to manually enter the IP adresses for each database that I create. Is there a way around this?