net.minecraft.launchwrapper.Launch ignores username and session id

I used Minecraft Launchwrapper to install Minecraft Forge without modifying Minecraft files (see http://www.6minecraft.net/how-to-install-minecraft-forge-in-minecraft-1-6-1-guide/ for details), but when game starts it assigns random playername and session id, because it completly ignores Username and Session arguments sent by Minecraft Launcher. Relevant Development console log attached.