Try this:-

• Load the closet and door prop and position as required.
• Open the hierarchy window and drag "door" on top of "closet" thus parenting the door to the closet. You could also achieved this in the Object/Properties dialog.
• Select the view from top camera.
• Open the joint editor (Window/Joint Editor)
• In the drop down list at the top of the Joint Editor select center.
• In the document window drag the green center cross hairs to where the hinge will be.
• Back to main camera view
• Select the door and turn the yRotate dial. The door should open.
• Double click this yRotate dial to bring up its edit window. You can now rename it "open-close" and if required set its limits. Click OK
• Finally, again if required, go to Figure/use limits

That should do it :)