I can confirm that this feature has been changed with Acrobat XI; in Acrobat X, it was possible to select it, to specify a profile, and the colors were converted to that profile, and that profile was set as Output Intent.
In Acrobat XI, one has to first specify the Output Intent (which would mean an according Fixup in Preflight). Then, it is possible to do the color conversion.
But then, one could wonder why not do the color conversion in Preflight.
Hope this can help.