How do I get trimmed alphas in xsi 2010?

[sirdavid32]

Hello, I´ve been trying to get trimmed alphas by turning off the "enable" material checkmark and also by overriding it with diffuse_in_use (unchecked) from the parameter list, and also by testing visibility options from the view menu of the object. None of these methods have given me results trimming a clean cut occlusion for near shapes over far shapes in front of the camera the way they used to show in xsi 4 videos.

If it be possible, could anyone point me the right steps to do this in xsi 2010? I can´t get this right. Everytime I trie the above , the partition only shades my material in pure black.
Help.

Thanks.

[NNois]

have you checked that the "a" color slider value in occlusion is set at 1 ?
the default softimage value in 2010 and olders put 0 alpha on the dark color of the occlusion node...

Otherwise you could use some pick channel nodes and a rgba combine node to override the alpha