thanks for your replies; sorry the late reaction, but were 2 hectic weeks, where QV was not the only project.
About the service account, we do need to use 2 service accounts, as per company's security policy. However, after a bit of a fight, we were able to set it up...
Not an easy task, but once you are there, all become obvious
Just for future reference, we need to go through the custom install, and select service by service. Also, the use of 2 service accounts, one for the internal network and another for the DMZ is achievable, but there are a couple of tricks to know... And finally, the order by which the licenses are applied is very important!
Once again, thanks for your replies...