Well, i don't use the FTB launcher because of the lag issues, however there is an advanced options under the options tab in the FTB launcher that allows you to put your own java parameters in. Just copy and paste the java argument given (look in the minecraft folder in the Tolkiencraft folder for FTB). Otherwise, the FAQ (found in the op) will help too.I'm using the FTB launcher for it, unsure of what you mean?