I'm not an expert, but I wanted to try and lend a hand.
The Auctiva "storefront" is kind of a misnomer - it is just another place your current auctions are gathered (like the scrolling store window) except that in the storefront you can tidy it up a little and make categories...like eBay stores without the $15 fee. (I can get to my store by clicking the store window I have in my auctions, but I worked on my storefront first and put promotional text in the bottom of my store window...since that text is what I click to get to my storefront, you may have to do that first.)
What it is is sort of a full-page version of our scrolling store windows that eBay browsers can click on to see all our stuff on one page. You can customize your store if you go to the tabs on the top of this screen -
Store Tab > Store Settings > (choose either style, I happen to like 1 > this will bring you to a screen where everything is pretty well explained for you.
As far as I know, what you list via Auctiva, which all ends up in your storefront if I'm not mistaken - so it's the same thing - is NOT submitted to search engines. You can do this manually, I believe some sellers like to do this, on www.googlebase.com
Also, if you have an eBay store ($15 fee - ouch!) you can submit your listings to search engines (it's the least they can do! Sheesh!)
-Fox