after small game I found out interesting feature - SATA HDD
is supported in official code!

May be I again invented wheels, but for those who not known that
alread I show small workaround how to get internal HDD (SATA)
supported by main software (pvrmain).

It is very easy - if you succeede soldering SATA connector
to to mainboard (it means soldering 4 pins only, so should
be doable even by not experienced users), then you get
recordings there. The recommended workaround is
doing the following - plug USB flash disk, wait few seconds
to get flash disk recognized by linux and then remove it again.
Now you can see on front panel's display lighting symbol "HDD".

After that you can use internal disk same way like external usb one.

Oh, forgot to note: you can preformat disk anywhere else. This
way I got working EXT3 filesystem on it. If you use built-in
option for formating drive, you get it preformated to FAT32
(Vlad: )

BTW, I think there must be way to signal to system that internal
sata disk is running (to get it detected), but currently I wanted
to share my experiences with SATA, so this is a reason for workaround.
Later, if nobody else do it before me, I will try to find way
how to signal existence of SATA disk to application without
such crazy workaround.