A cursory test seems to suggest that this is a function of IE.
If I run the PrintBrowserWindow command from a script, the print dialog comes up, but Print Center doesn’t yet launch.
IE’s dictionary doesn’t show any parameters for the PrintBrowserWindow command, which is where you would find something like “without dialogs” as an optional parameter, if it existed.
Sorry to be the bringer of bad news, but it would appear that IE’s X version just doesn’t to this as nicely as 9?