Hello
What is the goal?
If it's to insert an assembly several times into another assembly, I advise you to look at the copy function with the constraints by holding shift and clicking on all the parts or on the assembly you want to copy: http://help.solidworks.com/2012/french/Solidworks/sldworks/c_copying_with_mates.htm
Or multiple constraints:
http://help.solidworks.com/2011/french/SolidWorks/tolanalyst/LegacyHelp/TolAnalyst/topics/Applying_Multiple_Constraints_to_Features.htm?id=a27ea5cce04e4c68b08c56b87aa53854
But it is not possible to directly retrieve the smart part of a part in an assembly.
All these tips can be found in my beginner SolidWorks tutorial ;-)
http://www.lynkoa.com/tutos/3d/astuces-debutants-solidworks-1