How can I retrieve Field-Level Security Settings for Task object fields using MetaData API

Question

I'm trying to retrieve Field-Level Security Settings for Task object standard fields like Comments or Name using MetaData API. I was trying a 'retrieve' request like this:

 <retrieve>
    <retrieveRequest>
        <apiVersion>31.0</apiVersion>
        <unpackaged>
            <types>
                <members>*</members>
                <name>Profile</name>
            </types>
            <types>
                <members>Task</members>
                <name>CustomObject</name>
            </types>
            <version>31.0</version>
        </unpackaged>
    </retrieveRequest>
</retrieve>

But there is a different set of fields and their settings in the output.

I was also trying to get them directly, but getting an error 'Entity of type 'CustomField' named 'Task.Name' cannot be found'

    <types>
        <members>Task.Name</members>
        <name>CustomField</name>
    </types>

How can I get the visibility settings of the standard fields ('Related To' for example) for some profile?