I got mine to work by using the following. Took me a few hours... :x
None of the others seemed to work for me.
The models/textures show up in hammer and compile works puting the bsp into the correct directory automatically.
"Exterminatus"
{
"GameDir" "c:\program files\steam\SteamApps\SourceMods\ex"
"hammer"
{
"GameData0" "c:\program files\steam\steamapps\SourceMods\ex\ex.fgd"
"TextureFormat" "5"
"MapFormat" "4"
"DefaultTextureScale" "0.250000"
"DefaultLightmapScale" "16"
"GameExe" "c:\program files\steam\steamapps\brontohl@hotmail.com\half-life 2\hl2.exe"
"DefaultSolidEntity" "func_detail"
"DefaultPointEntity" "info_player_start"
"BSP" "c:\program files\steam\steamapps\brontohl@hotmail.com\sourcesdk\bin\ep1\bin\vbsp.exe"
"Vis" "c:\program files\steam\steamapps\brontohl@hotmail.com\sourcesdk\bin\ep1\bin\vvis.exe"
"Light" "c:\program files\steam\steamapps\brontohl@hotmail.com\sourcesdk\bin\ep1\bin\vrad.exe"
"GameExeDir" "c:\program files\steam\steamapps\brontohl@hotmail.com\half-life 2"
"MapDir" "c:\program files\steam\steamApps\SourceMods\ex\maps"
"BSPDir" "c:\program files\steam\steamapps\SourceMods\ex\maps"
"CordonTexture" "tools\toolsskybox"
"MaterialExcludeCount" "0"
}