FTP readonly settings for folder files

am using Smart FTP

[benevolent001]

Hi i am trying to creat a user account for FTP with read only access to the files in that folder

here is what i have done and problem i am facing

1) I created the new ftp user ftpuser in site control panel and the folder for the same user was created at following location

/ftp/pub/ftpuser

2) I uploaded all the files into the folder

Now i want to give this user login details to users of my website , but want that they should not be able to either add new files or edit or delete present files

To do that i tried to give permissions
444 to the folder ftpuser
But in this when i login to the ftp using the account details of ftpuser and not able to see the files

But when i set those permissions to 744 it shows the files , but now the ftpuser can edit files and can detele or upload new files which i dont want

How can i do that ftpuser is give readonly access to the folder files

suggest me some other method if am not using the best way out

thanks in advance