Dear Jack;
Both Desktop and Solidworks can produce .stl ( 3D stereolithography) files form their native solids. If your 3d wireframe is a standard autocad file, desktop can probably import it. I have a feeling that LT does not support true 3d, although I know you can draw in 3d with it.
After importing your wireframe, you would still have to surface your wireframe model, and then turn that surfaced model into a solid before you could create an .stl file.
All of these things are difficult and time consuming at the best of times. For what its worth, I think you would save time and aggravation redrawing your model as a solidin solidworks or desktop.
Regards Adrian