How can i see the return value of a function/method in Geben (Emacs remote debugging client for Xdebug)?

Question

Using Geben to debug PHP code with Emacs. Sometimes, while stepping in a method/function code, I encounter code like this:

   function someFunction($parameter)
   {
       (...)

=>     return (someOtherFunction($parameter) + $somePreviousResult) / 2;
   } 

The expression itself is not relevant. What i want to know is the value of that expression, that will be returned to the caller, before stepping out of the function call. Is there a way of doing this with Geben?

Thanks in advance.