[PROBLEM] HDD wakes up himself after some time

[feg]

Yea, nothing that I know. Maybe something time to time try to acces the drive, but I don't know how to check it. The LED diode on hdd doesn't show that something reads or writes data, HDD just waking up I don't know why.
In XBMC is a lot more packets than in Raspbian, so maybe some of them do it, but i can't check witch.

HDD has build-in sleep mechanism, so hdparm is useless. I thought this is it, but I removed it and issue is still valid - hdd goes slepp and after few minutes is waking up.
I also tried manually mounting drive in fstab insted of automount, but this is also not it.

I forgot write in first post - I'm using newest version of Xbian and it's rpi with 512mb memory.

You guys are my last chance