Found the solution.

Drag and drop the facebook plugin widget on your page
To the left of the window that appears, click the buttons (like, share ...) one by one that you want to include
Paste the url of your facbook page in the URL window
Choose the style of button (small, how to count) from the drop down boxes
Scroll down a bit and hit the "get code" button
Copy the code of the first box and the 2nd box to wordpad or in some text editor
Draw a small placeholder (rectangle) in xara on your page
Right-click and web properties
Paste the first code in the header part; paste the second code in the HTML/body part
You'r done ! Preview