UV Targa mapping

Is anyone out there having success using Blender for UV maps of complicated meshes for use in the Second Life modeler? I get partial rez, but then it makes a haywire blob from the TGA. I’m modeling in Solidworks and AutoCAD. I get great VRML imports into Blender with a very high degree of detail, and nice UV maps in TGA that are tight to the Unwrap as well as responsivel to margin changes to fill the map. I easily add full length seams by selecting just two vertices for the path.
Are there limitations to the SL modeler that are causing this? My models render beautifully in the native software.