slimbuilder does not work for multimain builds

[pYr0x]

i tried to use the slim loader to build a multimain bundle.

var path = require("path");
var stealTools = require("steal-tools");

var promise = stealTools.optimize({
  main: ["main1", "main2"],
  config: path.join(__dirname, "package.json!npm")
}, {
  minify: false,
  debug: true
});

the loader is not put in each of the mains. the loader is put in a shared bundle.
i created a failing test.
https://github.com/stealjs/steal-tools/tree/slim-multimain