Hi Neal,
I am not sure whether it will work for you or not, but I would like to introduce you about the Apache Jmeter.
Actually, We had a standalone envrmnt, where we used Jmeter to generate the load by hitting the sequence of URL's. As a result, in Investigator we see synthetic users loggin In and using our web application. We can assign no. of users logging in a particular time frame from a remote system.
Regards,
Vaibhav