Hi janrosben,
Welcome to Auctiva! In order to add a counter to your listings when creating them through Auctiva, you just need to select one of the "Sellathon Counter" options from the "Select a Counter" pull-dowm menu on the Auctiva lister page. However, if you would like to add the eBay counter to your Auctiva created listings, the only way to do so would be to add it by revising your listings they're posted.
The reason you cannot currently select a counter when creating your listings through Auctiva is because you have not created a free Sellathon account yet. In order to create your free Sellathon account, just click the "Create a Sellathon Account" link beneath the greyed out "Select a Counter" pull down menu on the Auctiva lister page. Once you have created a Sellathon account, this menu will no longer be greyed out, and you will be able to select a counter when creating listings through your Auctiva account.
Also, in order to specify the condition and other specifics about the item you are selling, you just need to fill in the "Item Specifics" section. In order to enter this information when creating your listings through Auctiva, you just need to click the "Choose Item Specifics" link that appears directly beneath the "Category" field once you've selected your primary listing category.
Any additional questions or concerns? Please file a support request using the appropriate link on our help page: http://www.auctiva.com/free-auction-software-help/help.aspx
-Mike