I'm sitting behind an http proxy which Steam refuses to go through. Trying Proxifier to fix the solution rendered an error about having to use an https proxy, though research shows that it shouldn't need one.

Is it possible to make a target parameter in a shortcut?

ie. "C:\Program Files\Steam\Steam.exe" --http-proxy=myusername:mypassword@SERVERNAME:8080

I have the server name and port number, though I'm yet to understand the relevance of 'myusername:mypassword', or infact which username and password these instructions were referring to.

Of course, if a target parameter wouldn't work, would there be another way to get Steam to work?