Ok, so this might be a longshot, but: In previous versions we've used the following code to alter the output from pageref-propertys, but now with CMS 5 pageLink always ends up as null, which implies that PropertyPageReference isn'nt compatible with HyperLink. Does somebody know why, and maybe have a suggestion for a workaroud?

        protected override void AddedControl(System.Web.UI.Control control, int index)
        {
            try
            {
                switch(this.InnerProperty.GetType().ToString())
                {
                    case "EPiServer.Core.PropertyPageReference" :
                        base.AddedControl(control, index);
                        HyperLink pageLink = control as HyperLink;
                        if(pageLink != null)
                        {
                               //do stuff with pageLink here

                        }
                    break;

                }

            }
        }