dev-featurecomposer

I have a branch tmp/master that I merge pull requests in before they drive at the upstream master... I want my source to update to that branch...

// from my project composer.json
    "repositories": [
        {
            "type": "vcs",
            "url": "http://github.com/basz/BaconAssetLoader"
        },
        {
            "type": "vcs",
            "url": "http://github.com/basz/SpeckMultisite"
        }
    ],
    "require": {
        "php": ">=5.3.3",
        "bacon/BaconAssetLoader" :"dev-tmp/master",
        "speckcommerce/SpeckMultisite": "dev-tmp/master",  <-- trying to update to this -->
        "zendframework/zendframework": "dev-master"
    },

However as you can see it installs an entirely different branch (feature/composer)
Rattletrap:juffrouwjansen-winkels.nl bas$ composer.phar update speckcommerce/SpeckMultisite
Updating dependencies                                                   
  - Updating speckcommerce/speckmultisite (dev-feature/composer)
    Checking out 4c7421eeb41bb9780333de4312a98fb068d5c9a8