Hi Cynthia,
All of the Giving Works charities that can be selected when listings directly through eBay should be selectable from the Giving Works charity selection interface within Auctiva as well, but we do have to conduct updates at times to import new charities.
If you are unable to find the charity you would like to contribute to on our site, please file a support request about that using the form on the following page of our site:
http://www.auctiva.com/help/requesthelp.aspx#Please be sure to include the name of the charity you are looking to see added when you file your support request!
-Mike