Customizing Blogger "Post a comment" link and open it in a Popup Window

The "post a comment line" can not be customized using the classical layout in blogger unless you hack your template as described here. So if you like the "post a comment" form open in a new Window than this solution is ok. The option to open it in a popup window is not documented. Here I discribe how the customized link can be hacked to open the blogger comment form in a a popup window on click.
First you have to follow the instructions of bloger help and find out your Blog ID. If you want to open the post comment field in a new window you could use the code as suggested by blogger. It should look similar to this:

<a href="http://www.blogger.com/comment.g?blogID=1234567&postID=<$BlogItemNumber$>">You want to talk to me?</a>

where 1234567 should be replaced by you blog id and "You want to talk to me?" by the line you want to appear as the link to you comments form of you blog.
However, there is no way documented to open that form in a pop up window with a customized link. To do that you have to replace <$BlogItemCreate$> with the following code in your template:

<a class="comment-link" href="http://www.blogger.com/comment.g?blogID=1234567&postID=<$BlogItemNumber$>&amp;isPopup=true" onclick="window.open(this.href, 'bloggerPopup', 'toolbar=0,scrollbars=1,location=0,statusbar=1,menubar=0,resizable=1,width=400,height=450');return false;">You want to talk to me?</a>

Again, you have to edit 1234567 to match your blog ID and replace "You want to talk to me?" by the text you want to appear as the link to your comments input form.
Try yourself >> You want to talk to me?
Et voilá, if you now click on the link your comments form will open in a popup
window.