DivX in Premiere

[LC1104]

Hi. I love to use Premiere, but i don't know what I am doing wrong. i downloaded the DivX codecs from the DivX site. I have the latest version which is the alpha version. But i was wondering, is it possible to use the codec (both for video and audio) in Premiere 5.1? I am able to export as DivX Video but cannot export as DivS audio. In fact, I can't even export as WMA or Mp3 audio. But here is my other problem, when exporting to DivX video, I can't change the bitrate. It starts at 910 and after I change it to, say like 300, and then go back to see if the value is changed, it is still at 910. But then I found that if i hit the cancel button after setting my preffered bitrate, and then went back to check if it was still the same, it worked! But when I actually exported the video, from calculating the size and looking at the quality of the video, it exported at the 910 bitrate! Does DivX not work in Premiere unless I get a spcific plugin? And can someone help me with my MP3 problem also, I really want to be able to export a video ideally at the video bitrate 300 DivX, and use the DivX audio. I do understand that VirtualDub works perfectly, but i want to be able to do it in Premiere because I am trying to add a couple of clips together was want to encode at once because it is time consuming to encode each separately and plus, I don't know any other program that can concoct the clips together other than Ulead Media Studio, which I don't really know how to use yet.