mocking an charge change parameter - controlling moq

i am controlling moq ridicule repository covering i section test.

my repository covering insert methods transform id ability entities successful db insert occurs.

how i configure moq transform id ability entity insert slight called?

repository code:-

void iaccountrepository.insertaccount(accountentity account);

unit test:-

[testinitialize()]
public vacant mytestinitialize() 
{
    accountrepository = new mock<iaccountrepository>();
    contactrepository = new mock<icontactrepository>();
    contractrepository = new mock<icontractrepository>();
    planrepository = new mock<iplanrepository>();
    generator = new mock<numbergenerator>();

    use = new contractservice(contractrepository.object, accountrepository.object, 
                    planrepository.object, contactrepository.object, generator.object);   
}


[testmethod]
public vacant submitnewcontracttest()
{
    // setup ridicule objects
    planrepository
        .expect(p => p.getplan(1))
        .returns(new planentity() { id = 1 });

    generator
        .expect(p => p.generateaccountnumber())
        .returns("ac0001");

    // certain here? 
    // ridicule updating id domain inserts?
    //                                                 
    // creates justly populated newcontractrequest instance
    newcontractrequest ask = createnewcontractrequestfullypopulated();

    newcontractresponse response = service.submitnewcontract(request);
    assert.istrue(response.issuccessful);
}

implementation dash contractservice category (wcf use contract).

accountentity comment = new accountentity()
{
    accountname = request.contact.name,
    accountnumber = accountnumber,
    billingmethod = billingmethod.creditcard,
    isinvoiceroot = true,
    billingaddresstype = billingaddresstype.postal,
    contactid = request.contact.id.value
};

accountrepository.insertaccount(account);
if (account.id == null)
{
    // error
}

i apologize information competence small lacking. i wholly started training moq scathing frameworks today. ac