I am afraid you may not be able to convert A2 models using Lithunwrap 1.3. Depending on how desparate you are, you may want to check out Ultimate Unwrap ($50?). I think that that is what Major Payne uses, but he has been little or no help to me in this regard.
I also know that there is a Milkshape sod importer out there with the stock restriction unlocked, but Phantom at armadafleetcommand.com is the only one with it. I also have looked at and have the source code for the locked importer and believe I can unlock it, if someone can compile a C++ program. We have all the resources we need to get this done except someone willing to recompile the sourcecode.