If you have the express tools, check out the layer options. For example you can use the layer merge to merge your layers into a selected layer. You can also use the layer delete to delete layers you do not use.
This probably won't work, but have you tried loading the .mnu from the full version of AutoCAD to 2005 LT? I too have been very interested to find out if there is a way to do this.
Instead of using "solprof" to create the top and the other two views, use "solview", and "soldraw instead. Then you should be able to change the layer linetypes.