SSIS2012 Parent PKG Call With Parameters a Child PKG transfers empty value when in StoredPackages

Hi

I have developed a simple Parent/Child PKGs in SSIS 

In the parent I send using parameters values to the child PKG

When testing it in VS2010 , all works well ( the value is sent to a StoredProcedure which updates the DB )

But After deploying ( importing ) the child to the SSIS StoredPackages , when running the Parent PKG from the StorePackages or from the VS2010 , in neither case , the value isn't passed from the parent to the child PKG

Have I missed something ? do I do something wrong ?

BTW , I prefer NOT to use "variables" option , unless there is no other way
( I prefer not to use it because I read about it and still didn;t understand the logic of it all )