Facebook Mirroring only works with ugly urls

[Masweb]

I'm using CGBlog, CG Headmaster and CG Facebook Post to post a CGBlog item on a Facebook Page. That works fine.

On the website I use also a Facebook comment field.
On Facebook you have the possibility to mirror comments.
If someone put a comment on Facebook it will be displayed on the website and if someone post a comment on the website it will be visible on Facebook.

After a long time and a lot of tweaking I figured out that this only works if you use the original ugly urls.

With HeadMaster I get the url of the article with this tag:

{cghm_config_set key='canonical' val=$entry->canonical|default:''}

That print the friendly url in the head of the page.
Is there a way to display the ugly url of the article over here so the Facebook mirroring will work?

[Rinker]

When I just use the facebook comments plugin people have to click a checkbox if they want to share the comments on facebook, this checkbox is shown as soon as you click the comments box.

[Masweb]

When I just use the facebook comments plugin people have to click a checkbox if they want to share the comments on facebook, this checkbox is shown as soon as you click the comments box.

Yes, but are the comments display'd on the website and on Facebook then or only on Facebook.
And second: Does your website have pretty url's?

My question is: I want to use pretty url's but need also the "dirty" url for the facebook mirror.