ANSWER:

DIR /S /B follows symlinks, so can do following (this is batch file, paste its contents to OEM (non-unicode) encoded file, say, archivewithsymlinks.cmd).
Note that there’s trick in last line to pass 7z exit error code out of script (without using intermediate variables).

@ECHO OFF
SETLOCAL
REM Note that 7z.exe must be in %PATH% or current directory, or just modify penultimate line.

IF NOT "%~1"=="" GOTO :TryAnotherListFileName
  ECHO Usage:
  ECHO %0 archivename sourcefiles...
  ECHO where:
  ECHO     archivename filename of archive file, where sourcefiles will be added
  ECHO     sourcefiles list of files to be added
  ECHO.
  ECHO     Also, %%parm7z%% variable can be defined and will be passed to 7-Zip before archivename
EXIT /B

:TryAnotherListFileName
SET filelist=%TEMP%archiving-%RANDOM%.list
IF EXIST "%filelist%" (
  ECHO Filename "%filelist%" already used for something. If that happens regularly, maybe it's time to change something in the batch file "%~f0".
  GOTO :TryAnotherListFileName
)

REM remember first argument before SHIFTing
SET ArchiveName=%1

:MoreSourcePaths
  DIR /S /B %2 >> "%filelist%"
  SHIFT
IF NOT "%~2"=="" GOTO :MoreSourcePaths

7z a %parm7z% -i"%filelist%" -- %ArchiveName%
DEL "%filelist%" & EXIT /B %ERRORLEVEL%

by LogicDaemon from http://superuser.com/questions/419920