Howto create/install a Freemarker transform

[Ruth Hoffman]

Hello all:
I'd like to write a simple Freemarker transform in Java and then have it 
available to all my templates across the entire instance of OFBiz. (This 
would be similar, I think, if I understand this correctly, to the 
<@ofbizContentUrl>  & <@ofbizUrl> directives.)  The question I have is:  
where do I install my transform once I've built it?  Or, maybe the 
question is:  how do I configure Freemarker to understand I now have a 
new global/shared variable? Any suggestions would be appreciated.

TIA
Ruth