Hello Colonel!
Sir!
If I understand your question Colonel, I'll try to offer this:
You don't really access your Auctiva Account "through" the Ebay website per-se'. What I mean here is that each one of the two websites (Ebay & Auctiva) have their own individual 'accounts' associated with you (or me) as patrons or 'users'.
You can have 'quick-access' to your Ebay-account and your Auctiva-account at the same time by having two different browser windows (or tabs) active in your browser simultaneously. I believe IE-7.0 uses tabs now (i don't use IE) and FireFox has had window tabbing forever!
The idea here is to first open a window(tab)in your browser. Then navigate to say Auctiva. Then login to your accnt at Auctiva. Ok?
...now
Open a NEW additional window(tab)in your browser. And using this NEW window, navigate to Ebay; and login to your accnt at Ebay!
Now you have quick access to each account by flip-flopping between the two browser windows. See?
I hope this helps.
Again, I hope I understood your intent. And I hope I haven't given anyone a bum-steer!
Zeb