XML Database synchronization

[Joel Guillod]

I would like to hear about advices how to address this problem in  
Revolution:

Postulates:
- data of my system is based on a number of sets of xml documents;
- a set is a repository of xml documents;
- there is a registry of the sets which references the address of  
each set;
- to avoid complicated installation on the machines where sets reside  
(i.e. not Java/python/php based).

Wanted functions:
- Revolution applications can access (read/write/update) xml  
documents throught the network;
- To be able to synchronize each set (in order to have mirrors sets  
of the xml documents);
- To index each xml document for fast query (xpath, xquery and  
xupdate in Rev 3, a dream? No a must, definitely!).

I am currently using eXist an Open Source Native XML Database (http:// 
exist-db.org/) but I need to have multiple sets of xml documents  
somewhere on the net and to be able to synchronize those sets.
I will be grateful to read any serious clue from developers actually  
knowing the topic.
JG