Step 1. Sign in at Facebook.
Step 2. Look for the Twitter application page and click the "go to app." Top of the page.
Step 3. Click "allow" on the admission application screen. This will give Twitter permission to your Facebook page to update. In this step, you probably need to Twitter.
Step 4. Click the "allow" button on the next page, giving Facebook the permission to your Twitter account.
Step 5. Type in a new Tweet on the Twitter web interface or via the Twitter client of your choice. At the end of the Tweet, type: # fb.
If there is "# fb" do not put your tweet will not be put on facebook. This allows you to see what messages there are two services.