Namco Bandai has released an update for the PC version of Ace Combat: Assault Horizon that lets players switch from Games for Windows Live to Steamworks functionality.
The update, which went live yesterday, lets you keep both your saves and achievements. There's more on the Steam page.
The update will be available until 1st April. From 1st April the new version of the game using Steamworks will become the default version. After 1st April, Namco Bandai can't guarantee your save files and achievements will be properly transferred, the publisher said.