Do you have QuickTime 7 installed, or just QuickTime X? You need QT7 for Premiere Pro export. I know I've got QT H.264 export, though I'm on Windows.
Might affect Flip4Mac, as well.
I would not be able to get any work done without QT7 installed. So, yes, it's installed.
I can work around this by exporting a higher resolution format, and transcode to H.264 in QT Pro or some other app, like Squeeze, MPEGStreamclip, etc. But that's doubling my work. I'm just wondering why it's not available to Premiere.
WMV isn't available to all applications, but it is directly exportable from FCP (with Flip4Mac installed). It's not available for export from Avid Media Composer (on Macs. I know it is for Windows.).
Answering my own post here: The H.264 export option IS available in Pr. I was looking in the wrong place: under Quicktime > H.264. That's where I found the H.261 and H.263 codecs. There's a separate drop-down menu for H.264 that I overlooked. I am so sorry for the false alarm.
Now that I'm getting more up to speed in Pr, I think that using AME for exports is way superior to doing them right from Pr. This is mainly because AME exports in the background, and you can set multiple export options.
However, exporting to WMV is still a two-step process for Macs. I've been exporting to ProRes first, and then using QT Pro to make the WMV. Again, not ideal, but it's something that can also be done as a BG process.