Mustang1977 wrote on Jan 20^th, 2015 at 12:41pm:

Don't know how compatible the 707 with the Steamversion is, but I don't think that there are problems with it.

The 707 works fine in the FSX Steam Edition (especially after the last update a few days ago).

These lines:

  <Launch.Addon>
    <Name>Captain Sim 707 Sound</Name>
    <Disabled>False</Disabled>
    <Path>Captain_Sim\707\cs.sound.dll</Path>
  </Launch.Addon>

must be entered into the FSX-SE DLL.XML file, to enable the sounds to work in the 707 in FSX Steam Edition.
NOTE. This can be difficult if the DLL.XML file doesn't already exist!