I found a way to do this that seems to work OK with some caveats on when the javascript might need to be available. I have a single javascript file included in my custom orbeon war file and it has the following in it
var head= document.getElementsByTagName('head')[0];
var jsfiles = ["/imStatic/scripts/jquery.min.js",
"/imStatic/scripts/jquery-ui.min.js",
"/imStatic/scripts/log4javascript.js",
"/imStatic/scripts/util.js",
"/imStatic/scripts/docview/logger-1.0.js",
"/imStatic/scripts/docview/jquery.ui.eventbus.js"
];
var index;
for(index=0; index<jsfiles.length; ++index)
{
var script= document.createElement('script');
script.type= 'text/javascript';
script.src= jsfiles[index];
head.appendChild(script);
}
This seems to work ok in the simple tests I have done so far.
It would be better if I could just add these to the property file but this will do for now if it works in all cases.