HDMI not working/enabled on AMD 6970

Hi! As the title says, the HDMI port is not working on my AMD Radeon 6970. I wanted to hook my PC up to my Toshiba Regza 42" LCD TV the other night, but it's not working. I've tried all 3 HDMI ports, none of them gives anything else than a blank black screen. The TV however, IS recognized by the PC in Catalyst Center. It didn't work connecting the HDMI port from the PC to my Dell 24" monitor. (I'm currently using the Mini DP for the Dell Monitor, which works like a charm.)

So, is there anything that needs to be "activated"? Is the product defect? Any clues?

PC:
Motherboard: ABit IP35
CPU: Intel Core 2 Quad Q6600 2,4GHz
GPU: AMD Radeon HD 6970 2GB vRAM
RAM: 4GB DDR2, 600MHz
SSD: Intel 80GB, can't remember what model.
HDD: 2TB WD 7200RPM
PSU: Corsair 850W

Help is highly appreciated!