The destination username and passowrd for the projector is set within the string sent.
Also in the projector setup authentication should be turned off,
and, ofcourse the ip of the computer must be in the same range as the projector!

For Example:
SYNTAX For sending commands to projectors
http://Username:Password@ip-of-projector/command

The defaut username is generally: 'admin1' or 'user1'
and the password is genrally 'panasonic' by default

So a lamp on command to a specific projector would look like this:
http://admin1:panasonic@192.168.0.14/cgi-bin/power_on.cgi

This syntax is relevant for most other commands, below is text file with a list of commands which I have
managed to test and prove using this method:
RTF text document: HTTP projector commands