New model instance with hasMany relationship from form data

I have two models:

// models/licenses.js
export default DS.Model.extend({
    name: DS.attr('string'),
    active: DS.attr('boolean'),
    territoryType: DS.attr('string'),
    territories: DS.hasMany('masterTerritory', { async: true }),
    cities: DS.hasMany('city', { async: true }),
});

and

// models/license-type.js
export default DS.Model.extend({
    primaryCity: DS.attr('string'),
    region: DS.attr('string'),
    licenseType: DS.belongsTo('licenseType', { async: true }),
});

I'm trying to create a new instance of the 'license' model from form data, including a select box containing licenseType data:

{{!-- templates/index.hbs --}}
...
{{view 'select'
    contentBinding='controller.ddLicenseTypes'
    optionLabelPath='content.name'
    optionValuePath='content.id'
    class='form-control'
    value=newLicenseType
    action='createLicense'
    prompt='Select a License Type'
}}
...

// controllers/index.js
...
ddLicenseTypes: function() {
    var store = this.get('store');
    return store.findAll('licenseType');
}.property('store'),
...
actions: {
    createLicense: function() {
        var store = this.get('store');
        var primaryCity = this.get('newPrimaryCity');
        var region = this.get('newRegion');
        var licenseTypeId = this.get('newLicenseType');
        if(!primaryCity.trim()) { return; }
        if(!region.trim()) { return; }
        if(!licenseTypeId) { return; }

        var license = this.store.createRecord('license', {
            primaryCity: primaryCity,
            region: region,
            licenseType: store.find('licenseType', licenseTypeId), // What do I do here?
        });

        this.set('newPrimaryCity', '');
        this.set('newRegion', '');
        this.set('newLicenseType', '');

        license.save();
    },
}

My problem (as noted by 'What do I do here?') is in converting the licenseTypeId I retrieve from the select input back into a licenseType model object. The code above leaves licenseType empty, so when I submit it to my server it inserts the record with a NULL licenseType.

I've tried using and several other permutations of that same theme, but I have not hit upon the correct answer.

Thank you for your help.