Costumized livecd on FreeBSD?

hallo guys,
I am new to freeBSD world, i want to have FreeBSD(small versiton) that run on the livecd, sort of other distors livecd.
it is just simple livecd, may be able to run shell script.
My question is that:
Do i need modify booting script in the iso file of freeBSD?, because in main menu during installation, they have "live filesystem" feature which similar like a livecd.
fresbieis the option?

Thanks for any help,
You can create your own small live-CD with sysutils/freesbie.
Thanks ale and lme@,
That was quick and good reply.
I will try those option, and give a output to you.
Thanks again.