With Alistair, all SRAM and Shimano FRONT's use the same pull, its only at the rear do SRAM X range use 1:1 pull while Shimano and named SRAM (such as Attack) use 2:1 and are therfore not compatable.
My MTB uses an X7 and Deore LX mech just fine (and Deore/XT for the rear).
As an aside, while it will work people never use shimano shifters and SRAM mechs at the front as SRAM fronts are just not as good as Shimano and can be a real PITA to get working right.
Simon