ZBrushCentral

why my displacement maps dont works? (Maya)

hello every one
i use zbrush 3.1 and maya 2008. for using displacement map i exactly do step by step like Scott Spencer. creating 32bit dis maps by MD3 with specified settings, importing to maya and creating shader and so on… but stil no displacement. i changed Alpha Gain and Alpha Offset many times. i think somthing is wrong about my maps because they are very washed out and low contrast. almost they are entierly 50% gray with a fantom of darkests grays so weak…:cry:
thanx guys