Hi Pedro.

I did like I said I would, and I did a complete uninstall of the 757 (including the 757-300 & 757-200F expansion models) from FSX, that included deleting the Windows Registry entries. I then did an install directly into FSX-SE, that required me to re-activate the products, which was done without any problems. It installed just like it would in FSX.

Then I did a one hour test flight from YMML to YSSY, and everything worked perfectly! Not only that, it worked better than it did in FSX. I either had a better frame rate, or FSX-SE handled the graphics/textures better than FSX does. Because of this, I can see and understand why some people are moving from FSX to FSX-SE!

NOTE: Because I still have FSX installed, the ACE was seeing my FSX installation and any changes I made, it was trying to make to a non-existent 757 Captain in FSX! I had change where it was looking for FSX (in the ACE Tools tab) so that any changes I made would work. That worked fine once I did it! Also, when loading a flight, FSX-SE went to my Documents\Flight Simulator X Files folder, instead of my Documents\Flight Simulator X - Steam Edition Files folder. Whether I changed something in FSX-SE so that it would do that, I don't remember. I did a lot of things to get the Captain Sim aircraft addons working in FSX-SE back when it was first released. The patches for FSX-SE since the initial release have eliminated the need for most, if not all, of them.

I hope that if FSX is not present, then the ACE will "see" FSX-SE as FSX, and of course that FSX-SE will search for flight in the correct folder.
One problem that I did find and may not be able to work around, is that the CDU/FMS saves and loads flights to my Documents\Flight Simulator X Files folder. I do not know how to change that. I'll see if I can find out how, but I make no guarantee that I will be able to.

One thing I would like to make very clear, is that I am NOT a member of the Captain Sim staff, or dev team!