Right, then we need to do extra work. Assuming that your kernel supports it (I have no idea if it will) you should be able to enable it by adding the vga parameter to your kernel boot line. To do so you need to edit either /etc/lilo.conf of /boot/grub/menu.lst. I haven't used lilo for ages, and I don't know if RHEL uses grub or lilo as its bootloader. You will have to find yourself or ask around if no one here knows.
In the case of grub, a tipical entry in menu.lst looks like this:
kernel /boot/vmlinuz 3 root=/dev/sdb1 vga=791
This is just a guide, don't copy-paste it, just look at the red example and modify your menu.lst file adding the vga=xxx stuff to your kernel line.
Mode 791 is 1024x768. You can use "vga=ask" instead if that doesn't work, and grub will present you with a list of valid modes the next time you boot so you can choose. After this, save the file and reboot. If your kernel has been compiled with fb support you should see smaller (and hopefully nicer) text than usual while booting, that will be a sign that the framebuffer is on. If not, then probably you will need to compile your own kernel, with fb support.