Try to put this button also to your blogger.
1. Go to blogger dashboard and click Layout and
click Edit HTML
2. Better to backup your template before editing this.
3. Press Ctrl+F and find this code
<data:post.body/>
4. Copy this below code after earlier code
<!-- DIGG --><div style="'float:right;"><script type="'text/javascript'">digg_url = '<data:post.url/>';</script><script src="'http://digg.com/tools/diggthis.js'" type="'text/javascript'/"></div>
5.Click "preview and see it correct and click "save template".