As of right now, if someone comes across your Auctiva store and clicks on an item, yes, it will take them to the Ebay listing. (I've run across Auctiva Stores while Googling) The Auctiva Store comes free when you sign up, we all have one.
However, sometime in the near future, Auctiva is introducing stand alone stores that will be seperate from Ebay. There were alot of discussions about this and wouldn't you know I can't find any links right now
As for Glory's question...I don't have an Ebay store and really don't know too much about them. If you CONSISTANTLY have alot of items to sell it might be a good idea. But store items are pretty much buried in a search, you need to have some regular auctions to drive people to your store. There are times when I have literally PAGES of auctions running on Ebay and they do just fine being auctions. There are alot of answers here that might help you make a decision:
http://cgi6.ebay.com/ws/eBayISAPI.dll?MfcISAPICommand=S...rchString=ebay+store