Can you tell me what version of iMC you are running? What operating system? Windows or Linux?
Also, what software version is the 5500-HI running? I just checked a 5500-HI in my lab and it does know about the SCP command. I'm running Comware Software, Version 5.20.99, Release 5501P01on the 5500-HI.
Also, on the 5500-HI in addition to turning on the SSH service, did you also turn on the FTP and SFTP servers? Does the login user have the rights to do sftp?
Comware does not come with services pre-enabled. It is up to you to turn on the services that you need. It's safer that way.
David