WinSCP access to SUDO user

I have a sudo user account in my system.
We use it to carry on common operations. More than one user has sudo user privilleges.
To access sudo user what i do is
1. Putty --> log in with my userID n pwd
2. Sudo su - sudouser's_ID
3. Prompt's for pwd : Enter my PWD (same PWD as for my userID)
4. ls... I am at sudo users hoem directory.

Life is good.
But when i have to copy something from my userID's hoem directory to sudouser's home directory
I have to use cp commands...
When i have a lot of file transfer to do ..i cnat do all of that in putty.

So i need to know HOW CAN I LOG IN INTO WINSCP using this SUDO account.
I wanna see all those direcories in WINSCP.
in WINSCP home i do have sudouser's directory next to mine, along with a folder for each user.
But when i try to open sudouser's directory, it shows me nothing there.

When I try to create a new session in WINSCP giving the user name of sudouser and my password..
again a new window opens with title
"Server Prompt" asking for password.

I looked online and found two links that i belive are talking about the same issue

you can go through them if you wnat

http://winscp.net/eng/docs/faq_su#use_sudo_on_login 



Another link has teh following content

"
I fought with this today and came up with the following solution:

Add a line to your sudoers file:
username ALL=NOPASSWD: /usr/lib/openssh/sftp-server

Then in the SFTP setup section of WinSCP edit the session SFTP server:
sudo /usr/lib/openssh/sftp-server

Boom, root access to file system via WinSCP.
HTH,
Clint
"

The above comment was found here http://winscp.net/forum/viewtopic.php?t=3046 

But i am not bale to comprehend it. Coz i dont know if thats the right way or if it is teh right way i donno how to do it.

What is sudoer's file ?

Thank You