Blogger API returning 400 on put request to edit URI

I'm trying to update a Blogger post using the protocol API provided by Google. I have creating new posts working just fine, but updating is causing me problems. I have the following code (Javascript):

        postRequest = new Ajax.Request("http://www.blogger.com/feeds/" + activeBlogID + "/posts/default/" + activePostID,
        {
            method: 'put',
            contentType: 'application/atom+xml',
            postBody: postXML,
            requestHeaders:
            {
                Authorization: 'GoogleLogin auth=' + authCode
            },
            onSuccess: this.postRequestSuccess.bind(this),
            onFailure: this.postRequestFailure.bind(this)
        });

But every time this comes back with a 400 Bad Request URI. As far as I can tell the URI is right (it's identical to the one in the 'edit' link element (I've checked), I just recreate it because it's easier than digging it out of the XML). I'm not seeing any problems with it but maybe I'm missing something. Suggestions?

Solution

Solved it myself. The issue was actually related to "PUT" being blocked over HTTP on the network. Used Google's suggested workaround in the documentation using "POST" to make it work.