Ah hah! I see.
Geek, is there not supposed to be a link to gmart_admincp.php?do=postage ??
I can't see it anywhere, but it does of course come up when entered manually.
Actually, now that I take a closer look at this, I don't think it's done for 3.5 yet.
acp_postage.gif
That's all I see.
Also, checking "delete" won't actually delete items from there yet. New bug?