PLL in LVDS mode, Cyclone II

Apologies if this has been covered before, I did a quick search of the forum..

This is my first time using LVDS with our Cyclone II device. I've used the ALTLVDS megafunction deserialiser and it seem to be just what I want. So far so good.

I also want to create a 10x LVDS clock output using a PLL. I can't get the "Create PLL in LVDS mode" button to light up. Does this not work in Cyclone II?

If I try to define a standard PLL pin output as LVDS, the fitter rejects it. If I send a single ended PLL clock signal to a LVDS pin as an output, it moans about jitter.

Am I attempting the impossibe??

:-)

Pete