OS X Wiki/Blog Server API

I'm working on a client app for iOS to edit the built-in Wiki/Blog on Mac OS X Server (Snow Leopard and Lion).

It seems that we are able to use MetaWeblog , Atom API(I've tried but failed) or XML-RPC. However, I can't find any API document for it.

So my question is, where can I find the documents, or some open source samples? All samples I found can't deal with the OS X Server.

Much appreciate!

Update:

Heres the standard structure of the Wiki system:

I can't even get the list of the 'group_name' under ~/Groups/

The javascript source code for the wiki is not obfuscated, and it seems simple enough to serve as documentation. For example, the authentication process:

sendAuthenticationPlain: function() {
    $('webauth').addClassName('verifying').removeClassName('error');
    var username = $F('username');
    var password = $F('password');
    var csrf = $F('authenticity_token');
    var plainResponse = "username="+username+"&password="+password
    this.setRememberMeCookie();
    var ajaxReq = new Ajax.Request(window.location.protocol + '//' + window.location.host + "/auth/plain_login", {
        method: 'post',
        requestHeaders: {'X-CSRF-Token': csrf},
        onComplete: this.gotAuthentication.bind(this),
        postBody: plainResponse
    });
    return false;
},
gotAuthentication: function(origRequest) {
    if (origRequest.responseJSON) {
        var jsonObject = origRequest.responseJSON
        if (jsonObject['success']) {
            var redirect = jsonObject['redirect'];
            var authToken = jsonObject['auth_token'];
            this.successCallback(authToken, redirect);
        } else {
            var errorString = jsonObject['error_string']
            this.failureCallback(errorString);
        }
    }
},

So you send a POST request to auth/plain_login, containing just the username/password in the POST data and an X-CSRF-Token header who's value comes from the <input type="hidden" name="authenticity_token" /> element on the page. The server returns a JSON string containing 'success' boolean.

You can also use safari/chrome's developer tools to monitor ajax requests to/from the server, for example this is the JSON contents of a PUT request to save a wiki page: