Disable sorting direction

I am building a search feature for my site, which uses CArrayDataProvider for data and CListView for display. There are two sort fields there: relevancy and date. I want to allow users to sort only by "relevancy DESC" and "date DESC".

Is this possible? Currently the user can change the sort direction by clicking on the "relevancy" link (once for ASC and once for DESC)…

This post is nearly one year old, but if you or someone would be still looking for an answer, then I think this post can be a little bit help.