Ruby: com object output parameter

Question

I'm working with WIN32 COM Object from Ruby via win32ole library

require "win32ole"

#~loading com object
o = WIN32OLE.new('{1A80830AF-4CA5-11D4-BC26-991045698E9C}') 
#~invoking "Process" method
o.Process(parameter_1,parameter_2)

"Process" method has two parameters: parameter_1 is input xml string and parameter_2 is output xml string parameter. How i can retrieve output parameter on ruby?

Thank you.