I've fixed my problem:
1)
First Step you must load with "SolidWorks" the .stl file keeping attention to activate in the options the voice "Solid Body"
2)
Second Step save your file with "SolidWorks" to "*x_b"
3)
Third Step Open the new "*x_b" file with "CoCreate Modelling"
IF there are problems to load "x_b" files from CoCreate you must use "MeshLab"
http://meshlab.sourceforge.net/
4)
Load your .stl file into "MeshLab".
5)
Select all the non-manifold vertices and delete them:
Go to “Filters > Selection > Select non Manifold vertices” to select.
Go to “Filters > Selection > Delete Selected Vertices” to delete.
After deleting all of the selected non-manifold vertices, some new non-manifold vertices may have created. Repeat the select and delete until no non-manifold vertices can be selected.
6)
Keeping attention to save the ".stl" file in ".stl"
Repeat Step 1-2-3
If you have problem to find in Cocreate "x_b" be shure to have selected the option "SAT" in "Interface"