report a bug about Composite key when call remove. #345

Hi,
When I call business_keypages.find({..}).remove(function() {...}), an error always occurs:
{ [Error: ER_BAD_FIELD_ERROR: Unknown column 'url,domain' in 'where clause'] code: 'ER_BAD_FIELD_ERROR', index: 0 }
My Model is follow:

module.exports = function (db, cb) {
    db.define("business_keypages", {
        domain: String,
        url: String,
        description: String,
        time: String
    }, {
        cache: 12 * 3600, 
        id: [ "url", "domain" ]
    });
    return cb();
};

To find the reason, I changed id: [ "url", "domain" ] to id: ["domain" , "url" ], and the corresponding part of error log also changed to be domain,url.
The orm version is latest 2.1.2.