Basically it boils down to "everyone beg Ravhin". And I wish I had a better answer, but I don't.
The wiki auction system (and anything wiki-related that requires a database) relies on custom PHP extensions, ie. PHP code that a player (Ravhin) wrote, and that Rogean then installed. If we want it to work differently, someone has to change that code, and convince Rogean to install the new version.
Ravhin made all that code publically available: there's a link to it at
http://wiki.project1999.com/utils/wikiUtils.php, and anyone who knows PHP could make the changes and send them to Rogean ... but so far no one has stepped up.
(And while I personally <3 the wiki, and even though I am a programmer ... and even though I
can write PHP, if someone puts a gun to my head ... let's just say I'm not a fan of that particular language.)