Can I mock this?

Hi,

I have been trying to create some unit tests for the following code:

void SecurityInitialized(PassedObject pObj) {
_dispatcher.BeginInvoke((CrossAppDomainDelegate) delegate() {

            try {
               pObj.DoSomething();
            }
            catch (Exception exception) {

            }
         });
      }

_dispatcher is an object of System.Windows.Forms.Form class. Is there a way to mock the pObj object from the inside of the BeginInvoke?

I have tried:

Mock pObjMock = MockManager.MockObject(typeof(PassedObject));
pObjMock.ExpectCall("DoSomething");

and calling the SecurityInitlialized method

but it does not work. Typemock says that:

Not all expectations where called:
Method PassedObject.DoSomething has 1 more expected calls.