copy freebsd src using sysinstall

[Shyaka Rene]

Hello, i'm learning freebsd server, i need to install src from dvd (internet cost is high in my country so i'm using DVD to install packages) mount dvd with command mount -t cd9660 /dev/cd0 /media/cdrom it works. the problem is when i use sysinstall to install src it show me an error dialog says error mounting /dev/cd0 on /dist:no such file or directory the /dist folder exists and google gives me nothing. any help is appreciated (i'm using freebsd version 9)