Running  slapd 2.4.10-3 version on debian 2.6.25-2-686

If I put a TAB (ascii character decimal 9)  starting a line in slapd.conf , 
in front of  syncrepl configuration option, the syncrepl funcionlity don't starts .
The fonfiguration test ( slaptest) return success.
If I delete the TAB character, syncrepl run ok