I've managed to figure it out
could you please tell us how you solved it?
Ok, got it. So you can adress it the same way as any other input parameters via the data attribute of the shader…
In our tutorial from last year's MAX, I showed how to use a two-input pixel bender kernel as a blend filter for two images on the stage. that is posted here:http://blogs.adobe.com/kevin.goldsmith/2008/12/materials_from_1.html
In one of my recent blog postings, I showed how to use a ShaderJob with multiple inputs. I was doing it for audio processing, but it works almost identically for images: http://blogs.adobe.com/kevin.goldsmith/2009/08/pixel_bender_au.html
Hopefully one of these should help, but if you have specific questions, don't hesitate to ask...