well guys after playing with my qnap ts-212 in raid 1, HDD spin down didnt work at all, so this is how i did get it to work.
using latest firmware TS-212_3.7.1_20120615.img
1.first i did a reset on the nas and went from a raid 1 setup to a 2 single drive setup.
2.went inside my router (wrt320n) and assigned an ip to my nas through DHCP Reservation.
3.rebooted nas and computer and finaly after 5 minutes my hdd,s went down.
sorry for my poor eng i thought maybe some ppl can do smth with this.