mocking free function using gmock

I am stuck in a problem and can't seem to find the solution.

I am using VS2005 Sp1 for compiling the code.

I have a global function:

A* foo();

I have a mock class

class MockA : public A {
public:
    MOCK_METHOD0 (bar, bool());
    ...
};

In the sources, it is accessed like this: foo()->bar(). I cannot find a way to mock this behavior. And I cannot change the sources, so the solution in google mock cook book is out of question.

Any help or pointers in the right direction will be highly appreciated. :)