Thanks to Miro for the info
Please read the following guide
http://www.minstrel.org.uk/papers/sftp/openssh5/
Download soruce of openssh
Replace the sft-server.c source with the one provided on the page above (or here)
compile it - the only thing we are going to need is the sftp-server binary
cd <source openssh>
make -j 10
after compilation finishes you should have sftp-server file
Make backup of your old sftp-server file
for standard solaris ssh installation
mv /usr/lib/ssh/sftp-server /usr/lib/ssh/sftp-server.ori
and copy the newly compiled sftp-server binary
cp <source openssh>/sftp-server /usr/lib/ssh/
chmod +s /usr/lib/ssh//sftp-server
Restart ssh and test if sftp access still works the same way as before
Now the chroot stuff comes
edit sftpsh.c file if needed and change the location of your sftp-server file
(or leave it as it is, it points to /usr/lib/ssh/sftp-server)
compile it
gcc sftpsh.c -o sftpsh
and copy it to some location
cp sftpsh /bin/
Edit /etc/passwd
change the shell of the chrooted sftp-only user to /bin/sftpsh
change users home directory so it is chrooted
example: /export/home/my_user change to /export/home/my_user/./
Now, it should work. please test