XCKn, TVout & PS2uartKeyboard, Arduino Mega2560

Hi!
I've been working on building a small computer with RCA NTSC output (using the TVout library), and PS2 keyboard input (using the PS2uartKeyboard library). The test sketch I've been running works fine on the Uno I was testing on, but doesn't work on the Mega 2560 that I want to use, because apparently, on the Mega/Mega 2560, "the XCKn pins are not broken out to header/pad" (according to the PS2uartKeyboard example sketch). When I try to operate the sketch on the Mega 2560, I'm rewarded with a blue screen on the TV that I'm displaying to.

My question is: is it possible to use these libraries in conjunction with an Arduino Mega 2560? Possibly something with the XCK1 pin I can see in this diagram (pin #48)?