Hi,
I appreciate the problem, as clicking on the Profiles tab doesn't "always" present the full profile options page that the old tab provided. Note to Auctiva developers: This appears to be a navigational problem connected with the facelift change. It's not on the navigation drop-down and isn't intuitive to locate.
Try clicking twice or switch to Manage and back. When you get the full page, click on the Manage Seller Details in the right column.
Danno