Using a struct throughout a m-file s-function

Hi

I'm writing a Level2 Matlab s-function and am having trouble with structures. I create a structure by making a call to a matlab function in the Start section as follows:

    radarData = readRadarResimFiles();

I want to be able to use the structure radarData in the Outputs block but I get the following "Undefined function or variable 'radarData'." I have tried declaring radarData as global in a number of different sections of my s-function, but to no avail. Any suggestions would be appreciated.

I am using 2011b.

Thanks...

Mike