After reading about this, I think I've solved it.
Basically there is no HDMI (A) to DVI dual link whatsoever, they are incompatible.
The triplehead2go needs a dual link because the resolution requires a pixel clock rate above 165 MHz, which is the limit for single link DVI. There are cables and adapters out there with HDMI in one end and DVI-DL in the other, but that is just a marketing bluff. The six center pins on the DVI aren't really connected to anything.
In the future there will be an HDMI (B) connector which is wider, has more pins and is compatible with dual link.
You may close this thread now.
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Thanks,
Knut Andreas Frøyen