New features released in fall 2013 allow faculty members to post individual syllabus sessions in the Syllabus tool, but also have them represented in the Calendar tool as well.
To start, enable the Syllabus tool and then click "Create Multiple Sessions" at the top of the Syllabus page. If you intend to add the items to the Calendar, select the "Create syllabus items by dates" option. Choose the beginning/end dates and appropriate time of day and day(s) of the week. Be sure to select "Display dates on calendar". Click the "Post" or "Save Draft" ("Post" makes items viewable by students and "Save Draft" saves the syllabus items, but keeps them hidden from students... here's another article about posting syllabus sessions).
If your Syllabus already exists and you would like to post the individual syllabus sessions to the Calendar tool - visit your Syllabus tool and click the "Bulk Edit" link. For each syllabus session, select the beginning/end dates (down to the minute). You must then check the "Calendar" option for each topic you would like added to the calendar. Go to your calendar, and make sure your syllabus sessions have been added.