Compare char with ampersand in AIF or SETB

Hello:

I'm trying to figure our how to code a SETB instruction to check if a
one-byte character string contains an ampersand, an apostrophe or a hyphen.
Apost and hyphen work fine, but I can't find a way to get a match with the
ampersand.  See my test case below.  Thanks in advance for your help.

--
Gilbert Saint-Flour
http://gsf-soft.com


//GILBERTM JOB (ACCT#),STRING,
// NOTIFY=&SYSUID,
// CLASS=A,MSGCLASS=X,COND=(0,NE)
//HLASM EXEC PGM=ASMA90,PARM=(NOOBJECT,NORXREF)
MACRO
&NAME    STRING
&I       SETA  1
&J       SETA  2
.*LOOP
.LIT11C  ANOP
&K       SETC  '&SYSLIST(&I)'(&J,1)
&B       SETB  ('&K' EQ '&&' OR '&K' EQ '''' OR '&K' EQ '-')
MNOTE '     J=&J KK=&K&K B=&B '
&J       SETA  &J+1
AIF   (&J LT K'&SYSLIST(&I) ).LIT11C
.*ENDLOOP
MEND
 ****************************************
***********************
STRING '&&'
STRING ''''
STRING '--'
END
//SYSPRINT DD SYSOUT=*
//SYSLIB   DD DSN=SYS1.MACLIB,DISP=SHR
//SYSUT1   DD UNIT=VIO,SPACE=(CYL,2)