It seems that it is disabled by Software
I don't see the reason for disabling it.
Try the update maybe it was re-enabled.
From what I understand it is only the Sprint Version that has this problem.
Maybe You need to Flash it to the Official Samsung Firmware
. (Scroll down for the Firmwares).
I can't tell for sure if the hardware supports it, but I have a gut feeling it should. It is entirely possible that the module required to do TV-out was left out to accommodate the Keyboard, but the Galaxy S line runs on a SoC standard and usually bundles everything together. (SoC = System On chip, like a motherboard with Audio, Lan, VGA, etc all soldiered in by standard). Although I don't know if the TV-out Module is separately attached (I doubt it). I don't see the benefit of rolling out a different SoC just for the Epic it would increase costs.
I guess since my phone is in piece I could find that out. Meanwhile, I think you should look into flashing you phone to an open firmware.