eBay sucks, that's the problem.
The most efficient solution I've found so far is to create the listing with
Auction Listing Creator (most straightforward to use), upload it via SunriseBrowser (fastest), then add the shipping info via OmniWeb (slow as molasses but a necessary step, because SunriseBrowser doesn't load the entire page).
You might want to employ an agent to auction your stuff, let him worry about it.
If somebody had paid me for all the time I've wasted listing auctions, I'd be a rich man by now.