Default value selection for drop down list / combobox

[jpearsonva]

Hi all,
I'm newer to knockout and trying to work on a form I inherited.  Basically, have a combobox (it's a dropdownlist but also a combobox since it can dynamically add a new item to the list) and I'm having trouble figuring out how to have a default value selected.  Right now it defaults to the caption text "Select...".

Here's the html and options for the control:

<combobox id="type"
                        params="options: $root.Type.choices,
                                value: type,
                                text: 'name',
                                valueConstructor: function (name) {
                                    return new $root.Type({name: name});
                                }">
                    </combobox>


View Model:

var Type = buildViewModel(
          
            function (data) {
                var self = this;

               
                data = data === undefined ? {} : data;

                self.id = data.id;
                self.name = data.name;
            },
            {
               
                list: "All_Types",
                mapping: {
                    "ID": "id",
                    "Name": "name"
                },
              
                generateSubmit: true,
              
                generateChoices: true,
               
                generateRetrieve: {
                   
                    data: function (auId) {
                        return dr.getMainToListData(
                            auId,
                            "au_Type_ID",
                            "au_Types");
                    }
                }
            }
        );

Later in the form, calling the observable for type:

self.type =
                    self.id() === undefined ?
                    ko.observable() :
                    Type.retrieve(self.id());

I think this is where I need to set the default value somehow (based on some examples I've seen)..but trying something like ko.observable(1) to set it to one of the choices just blows up the form.