my problem is not solved !!!
in webfig scan-list is not possible to modify:
in winbox .. yes !!!

see images here:
with winbox: http://ge.tt/1Ld0sAj2
with webfig: http://ge.tt/4b2UsAj2
http://ge.tt/5vtRsAj2

in version 6.36: webfig: http://ge.tt/952esAj2

bug ??
in webfig/wireless into wlan1 at scan-list is not posible to put anything... only select default... in winbox its posible to put a range of frequencys like 5200-5450 ...., until version 6.36 its works ok !!!

any idea?? solution ??

thanks