Is there anything else I have to do to start the program also as a normal user?
No, our products will only work with user accounts that have admin rights.
Note that, IT DOESN'T mean you have to run FSX with Admin rights. You are forced to do this, only because your user account doesn't have admin rights.
However, under Vista or Win7, even if your user account does have admin rights FSX (or any other program you launch that doesn't have a shield in its icon), will NOT run with Admin rights anyway. Using a user account that HAS Admin rights, FSX will not run with admin rights, unless you explicitely say so using the "Run as Administrator" command. BUT, the difference in this case, is that our products (any many others) will run without problems.
So, under Vista or Win7, there are no reasons not to enable admin rights to your normal user account, since applications (FSX included) will not run with admin rights anyway (unless you say so) so, there's no difference in security in this case.