How to download only one piece of file at a time with /tool fetch and put it inside a variable

[hkusulja]

Hello,
If somebody here knows, how can I use /tool fetch , to upload file (not bigger than 60 KB) from routeros to remote server via HTTP method?
http://forum.mikrotik.com/t/feature-request-tool-fetch-http-post-can-send-a-file/154710/10