The F1 FreeBSD followed by Default: F1 that you see when VirtualBSD boots, is FreeBSD's boot manager at work. Since there are no other operating systems to boot from on this virtual disk, you may as well get rid of it -- and save some precious seconds in the process at every boot! ;-)
1) Open a terminal (right click anywhere on the desktop and select Terminal from the menu).
2) Since you can't "sudo everything" in VirtualBSD, you need to become root. Type:
su -
and type the password (root4u) when prompted to do so.
3) Now that you are the superuser type:
fdisk -B ad0
4) Don't get scared by the output and, assuming you typed the previous command right, answer y at this prompt:
Do you want to change the boot code? [n]
5) Again, don't let the output scare you and answer y at the next prompt:
Should we write new partition table? [n]
Done! Starting with the next reboot you should see no F1 prompt and VirtualBSD will start booting right away.