I wanted to customize some changes in the beta, but using ISOMaster, it won't let me save a new one. The size shows 574mb in ISOMaster, but 701 in the directory. When I booted the iso, it showed that there was a module added during boot (metasploitz) but does not show up in the modules in ISOMaster.

Can the iso be customized, is it locked, or is it ISOMaster?