custom-provider not called

HI i am testing CustomProvider class registration in kentico cms version 7.0; i found that in some unknown conditions custom provider code was not called.

can anyone approve that in witch conditions system does not call custom provider code?(cache,callbacks or ?...)

I am register CustomCreditEventProvider in EcammerceMaduleLoader Init.

public override void Init()
    {
        EcommerceMethods.RegisterMethods();
        CreditEventInfoProvider.ProviderObject = new CustomCreditEventInfoProvider();
        ShoppingCartItemInfoProvider.ProviderObject = new CustomShoppingCartItemInfoProvider();

        SystemMethods.OnGetObject += SystemMethods_OnGetObject;

        ClassHelper.OnGetCustomClass += GetCustomClass;
        ObjectEvents.Insert.Before += Insert_Before;
        ObjectEvents.Update.Before += Update_Before;
    }

i found that ObjectEvents (Insert_Before,Update_Before) also not called.