there done omg so hard.OR you can just use the normal vanilla launcher and it doesnt use the FML check
.

try
{
FMLRelaunchLog.fine("Validating minecraft", new Object[0]);
Class loaderClazz = Class.forName("cpw.mods.fml.common.Loader", true, classLoader);
Method m = loaderClazz.getMethod("injectData", new Class[] { [Ljava.lang.Object.class });
m.invoke(null, new Object[] { FMLInjectionData.data() });
m = loaderClazz.getMethod("instance", new Class[0]);
m.invoke(null, new Object[0]);
FMLRelaunchLog.fine("Minecraft validated, launching...", new Object[0]);
}
catch (Exception e)
{
System.out.println("A CRITICAL PROBLEM OCCURED INITIALIZING MINECRAFT - LIKELY YOU HAVE AN INCORRECT VERSION FOR THIS FML");
throw new RuntimeException(e);
}

try {
applet = MinecraftLauncher.getMinecraftApplet(pack);
} catch (CorruptedMinecraftJarException corruption) {
corruption.printStackTrace();
} catch (MinecraftVerifyException verify) {
org.spoutcraft.launcher.api.Launcher.getLogger().log(Level.SEVERE, "Minecraft Verification error", verify);
org.spoutcraft.launcher.api.Launcher.clearCache(pack);
JOptionPane.showMessageDialog(getParent(), "Your Minecraft installation is corrupt, but has been cleaned. \nTry to login again.\n\n If that fails, close and restart the application.");
setVisible(false);
dispose();
org.spoutcraft.launcher.api.Launcher.getFrame().enableForm();
return;
}