Node.ACS - How to put controllers in subdirectories?

I'd like to organize controllers better by moving them to a subdirectory (e.g. a 'v1' subdir for version 1 of my API). However, when I do so, and update the config.json, my app won't load indicating that the controller paths are invalid.

{
  "routes":
  [
    { "path": "/v1/foo", "callback": "v1/foo#func" },
    { "path": "/v1/bar", "callback": "v1/bar#func" }
    { "path": "/", "callback": "application#index" }
  ],
  "filters":
  [
     { "path": "/", "callback": "" }
  ],
  "websockets":
  [
    { "event": "", "callback": ""}
  ]
}

I've tried with and without a leading slash, adding "./" to the beginning, etc. Regardless, I get:

[ERROR] Failed to load controller "v1". Error: EISDIR, illegal operation on a directory
    at Object.fs.readSync (fs.js:476:19)
    at Object.fs.readFileSync (fs.js:310:28)
    at loadConfig (/usr/local/lib/node_modules/acs/lib/command/run.js:362:20)

While I could modify run.js to do what I want, that wouldn't help once I publish to the cloud as it would be running stock code. The docs make no mention of how to do this, so maybe it's not possible. More likely I'm just being thick.