unless this is very new, i work as a ford tech in ontario, canada. i hooked my 2010 fusion to the ford server with our scan tool last week and only 4.4 was available. also just throwing in an APIM(acessory protocol interface module)(sync module) from another vehicle in my experience has not worked out well...programming issues. ill check tomorrow and see if 4.6 is available for me(in canada anyways)
Edit: checked today with ford scan tool, and in canada anyways, 4.6 is not available to install