Adding new Entry TO File Info Box .. Possible ??

[legend_neo]

HI.
Once again I m asking something that, perhaps, is not much appreciated. The thing is I m using CPG for a wallpaper based web. And I will be using many types of wallpaper from other webs as well. To give them credit, I want to add a new Link to file info box. Something like
"Main Site  ==  http://coppermine.sourceforge.net  "  

I Think one way of doing it is to put it in Image description box but for certain reasons, I m not using it in my theme. And File info box looks perfect for this.  
Any idea if this is possible???

Only admin should be able to add the web link and each pic will have its own Main Site link .

Hope to get guidance