HP PSC 1610 double-sided printing...

Hey all,

I've been noticing for a while since one of my reinstalls of the HP printer drivers and software for the aforementioned machine that my computer stopped being able to double-sided print at all. The option is always grayed out and I have no idea why. Does anyone know what could be causing, or does anyone have a similar problem? What confuses me is I'm sure that at some point in the past I was able to print in double-sided mode, but now I just can't. Any ideas?

I know that to print duplex (double-sides) when my Canon printer is attached to my iMac is much harder ... I mean there are more pull-down menus etc to navigate than if it's attached to my PC - where it only takes a couple of mouse clicks to set it up.