Hello David: Try the next.
After execute /*lh_config*/ with all your configuration, execute /*lh_bootstrap && lh_chroot.
*/When this process has finished, you can execute /*chroot chroot/*/ in the same folder in which you executed the previous command. Once you have chroot into the new debian live system, you can change the user full name as if you were in a normal debian, actually, you can do any change you want (install new packets, do some configurations, etc....), after that, execute /*lh_build.
*/Good Luck
