I find that only one file can be uploaded in plesk filemanager ???
you can go to net2ftp.com
And use this login info:
FTP server: plesk.lvcs.net
Port: 21
Username: yourusername
Anonymous: Untick
Password: yourpassword
Passive mode: Tick
Initial directory: /httpdocs/
SSL: Untick
Language: English
Skin: Blue
FTP mode
Automatic: Select
Binary: Deselect
yes, i have tried this, and i can also install a ftp script in my own webspace, but to my surprise, plesk can only hadle single file upload :'(