"keep" doesn't work with subfolders

[rhhamburg]

When I use keep with a folder how is direct in the root directory it works perfect.
My working example:

ftpush: {
    build: {
        auth: {
            host: 'server.com',
            port: 21,
            authKey: 'key'
        },
        src: 'dist',
        dest: '/',
        keep: ['/folder']
    }
}

But if I use keep with a subfolder, all elements in the subfolder and the subfolder itself will be deleted on the server.

I tested it with:

keep: ['/folder/subfolder']

keep: ['/folder/subfolder/']

keep: ['/folder/subfolder/*']

keep: ['/folder/subfolder/**']

but nothing works.

I use Windows 7 and Node.js 0.10.31.

[Valerio]

have you tried with keep: ['folder'] ?