%trimr and *loval

Why does %Trimr put *blanks on the end?  Or, better yet, is there a better 
way to make sure that the field ends in trailing nulls?  (As I finished 
typing up this last sentence I banged off a Sametime to the developer 
suggesting a variable length field instead.  I think it is a new file that 
he will be using for CPYTOSTMF or CPYTOIMPF for FTP EDI purposes thus he 
"should" be open minded...

     D MyVar           s             30a
     D MyString        s             30a   inz('test')

     C/FREE
       MyVar = *loval;
       MyVar = %TrimR(MyString);  // why does this put blanks on the 
end??????
       // the following needs to be improved in case MyString is full
       %subst(MyVar:%len(%trimr(MyString))+1:
                    %len(MyVar)-%len(%trimr(MyString)))=*loval;
       dsply MyVar;
       *INLR=*ON;
      /END-FREE

Rob Berendt
-- 
"They that can give up essential liberty to obtain a little temporary 
safety deserve neither liberty nor safety." 
Benjamin Franklin