Positions available in the template are
<positions>
<position>hornav</position>
<position>breadcrumbs</position>
<position>search</position>
<position>login</position>
<position>banner</position>
<position>footnav</position>
<position>left</position>
<position>right</position>
<position>top</position>
<position>user1</position>
<position>user2</position>
<position>user3</position>
<position>user4</position>
<position>user5</position>
<position>user6</position>
<position>user7</position>
<position>user8</position>
<position>user9</position>
<position>user10</position>
<position>user11</position>
<position>footer</position>
<position>syndicate</position>
<position>debug</position>
<position>content-mass-top</position>
<position>ja-login</position>
<position>sample</position>
<position>slogan</position>
<position>top-panel</position>
<position>top-panel-module</position>
</positions>
Still, if there are any module which creates its own positions, and you are sure it exists – just type in potion name in the drop-down position input box (it accepts not only items from the menu)