Do everything in 2.6 save it. Open the blend file in 2.49 and animate then export, it's not that hard.
Still, there's no incentive to do so. Most of the stuff can be done in the old Blender. Unless someone makes a better exporter for the new versions, I honestly see no reason to upgrade if you want to make stuff for BL. For other things, the new versions may be vastly superior.