Execute custom commands on Chinese filename,error occur.

Client: Windows 7 , WinSCP 5.5.4 (Build 4433) , SFTP protocol , UTF-8 encoding for filenames , Commander Interface
Server: Ubuntu Server 14.04 , OpenSSH_6.6p1 , LANG=zh_CN.UTF-8

When execute custom commands like "Tar/GZip(R)..." on Chinese filename "中文", then return error:
Command 'tar -cz -f "archive.tgz" "中文"' failed with return code 2 and error message ******.

thereinto, ****** are some garbled characters.

Thanks for your post.

This issue is being tracked already:
https://winscp.net/tracker/325