SQLDeveloper 4.0 preview: unable to run it

I have installed Java 7 and added 2 extra lines to sqldeveloper.bat:

cd C:\pierre\sqldeveloper-4\sqldeveloper\sqldeveloper\bin
sqldeveloper.bat

set JAVA_HOME=C:\pierre\Java\jdk1.7.0_45

set PATH=C:\pierre\Java\jdk1.7.0_45\bin

java -Xmx640M -Xms128M -Xverify:none -Doracle.ide.util.AddinPolicyUtils.OVERRIDE_FLAG=false -Dsun.java2d.
ddoffscreen=false -Dwindows.shell.font.languages= -XX:MaxPermSize=128M -Dide.AssertTracingDisabled=true -Doracle.ide.util.AddinPolicyUtils.OVERRIDE_FLAG=true -Djava.util.logging.config.file=logging.conf -Dsqldev.debug=false -Dide.conf="./sqldeveloper.conf" -Dide.startingcwd="." -classpath ../../ide/lib/ide-boot.jar oracle.ide.boot.Launcher

ERROR: You're trying to run the product with the legacy launcher oracle.ide.boot.Launcher . Check your .conf file and be sure to include:
        AddJavaLibFile  ../../ide/lib/fcpboot.jar
        SetMainClass    oracle.ide.osgi.boot.NbLauncher

I have added the 2 extra lines

AddJavaLibFile  ../../ide/lib/fcpboot.jar
SetMainClass    oracle.ide.osgi.boot.NbLauncher

to sqldeveloper.conf, but I still get the same error.
Giving up.
So sad.