Loopback MongoDB Connector: map properties to field names?

I'm using Loopback's MongoDB connector to expose a RESTful API to query and update a MongoDB collection.

When I defined the model it didn't let me define property names with spaces in them, so instead of "Gas 93" I had to use "gas93". The example is trivial but affect 9 properties of my collection.

I know you can map properties to table fields with the PostgreSQL connector

"properties": {
    "name": {
        "type": "String",
        "required": false,
        "postgresql": {
          "columnName": "username",
     }
 }

I haven't found a way to do the same for MongoDB fieldnames. I have a lot of features in my app using collection fieldNames as they are now, so I'd like to avoid changing them to adapt to loopback.

Is there a way to do this? Documentation doesn't say it but, then again, it doesn't say you can't either.