I'm very pleased with saving messages in files, moreover it can be encrypted also.

But sometimes I wanna save the files online, somewhere in my homepage or any other place....  'cause I use computers on work and at home.

Is there any method to save messages into online files..?

No because essentially it could be a breech of privacy. Someone could have the preferences locked out with a password and have the logs stored on a webserver for their own reading. So no this was never added and don't look for it to be. Plus! tries to limit the amount of times it actually needs to access the internet so.