Randall is absolutely correct. Latest version of Ghost boot wizard can add new entries but not pull the old ones out. We anticipated that people might try it out and once they are happy then they will delete the old contents and start afresh. lame excuse to not have this functionality available :( but due to time constraints we just couldnt do it in time and provide customers with reasonable queality feature.
We will be doing something about this in the next release. In the meantime please clean TFTPBOOT folder of BCD and WIM files.
Cheers.