I also desperately need the Custom Label field. Just went to Auctiva Feature Center, and there was 0 user rating for Custom Labels!! So I had the honor to be the first one to rate it.
If you want this field too, please rate it as well. If there aren't many users rating it, then I don't think they will prioritise this. Link is
http://www.auctiva.com/products/features.aspx
Thanks!!!