Here's what I've found out from my own experience..If you are a new seller to Ebay, your listings will almost always take 4-6 hours to show up. When you become more established, they'll show up immediately. I've been selling for 3 years and my auctions are always immediately searchable when I list now.
When you use Auctiva, being the 3rd party listing service that it is, Ebay will take longer to index your listings. If you have an Ebay store they will pull everything for a few hours (fraud check, etc). But I believe this only hapens the first time you use Auctiva. Anything after that is at the whim of indexing, which can be instantaneous, or a couple of hours. I haven't heard of a 24 hour index for a long time now, it's usually 4-6.
No matter what, your listings will return and be searchable..you just have to hang in there