This is the reason why the install CD should be used only for installing the base OS, and nothing else. No X, no additional packages, just the base.
Once you've booted into the OS, you can use the
ports(7) tree, or
pkg_add(8) to install any extra software you need. (You can mount the CDs and use pkg_add to add packages from them, if you don't have a fast Internet connection.)
It's too bad this isn't reinforced in the documentation. Although the sysinstall replacements seem to, thankfully, all take the tact of "the installer installs the OS, nothing more, nothing less, and is not a system configuration tool".
