BreezeJS modify a default key

Question

I am using breezeJS with Entity Framework to provide input labels for user input fields, using a ui-bootstrap modal dialog. Because I need an initialized entity, I also need to provide the entity with an entity key, which I believe is described at http://breeze.github.io/doc-js/inside-entity.html under "Detached entities." If I do not change the key value in the modal, all is well. However, that is supposed to be a placeholder key until the user inputs the appropriate key. When that occurs, manager.saveChanges() catches an error. I have tried initializing the entity as detached, completing the modal, then adding to the manager, but no success there either. Any ideas on how to initialize an entity with a default key which will be immediately be replaced by a user? Thanks!

//datacontext.js
        function saveChanges() {
            if (createItem.entityAspect.entityState.isDetached()) {
                manager.addEntity(createItem);
            }
            if (manager.hasChanges()) {
                manager.saveChanges()
                    .then(saveSucceeded)
                    .catch(saveFailed);
            } else {
                console.log("Nothing to save");
            }

            function saveSucceeded() {
                console.log("Save succeeded");
                return;
            }
            function saveFailed() {
                console.log("Save failed");
                return;
            }
        }


        function newItem() {
            createItem = manager.createEntity('Some_Entity_Type',
                { aPI: '1000001' }, breeze.EntityState.Detached);
            return createItem;
        };

Answer 1

It looks like the issue was initializing with an actual primary key value. Initializing with

        function newItem() {
        createItem = manager.createEntity('Some_Entity_Type',
            { aPI: 0 }, breeze.EntityState.Detached);
        return createItem;
    };

acts as a temporary placeholder until the user enters the actual key. My larger problem was resulting from having different types of input boxes in the ui-modal, where each was of type="text", so the key value was entered as text and an error was thrown.