They say "necessity is the mother of all invention." I don't really know who they are, but every now and then they're right.
This Lightwave 3D corner-pinning plugin takes up to 4 objects (usually nulls) and exports their 2D screen position keyframes into .fraw files suitable for importing into an Avid DS Tracker node. I do a lot of 3D animations for a TV manufacturer and it makes more sense to render them with empty screens and composite footage into them afterwards inside DS, making client revisions a bit less arduous.

Just pick your objects, choose a location and name to save to, and click Export. PinnedDown can also convert 24/30 fps keys into 23.98/29.97 for those that like to work in whole-number frames per second inside Lightwave (LW10 has some new and exciting bugs dealing with fractional framerates) but are actually comping in DS for broadcast.
This plugin should work on Lightwave 3D versions 6 and up, though I've only tested it in versions 9.6 and 10. Windows only, for 32 and 64-bit.