Search Order in REST 2.0

I see that REST 1.0 has an “orderby” parameter when searching tickets. I’m not finding a similar option in 2.0. I’ve tried different values for “orderby”, but they don’t have any affect on the output. I’ve also tried combing through the source code, without luck. I’m using 4.4.2, which already has RT::Extension::REST2 installed.

Any help would be most appreciated.