I may not be understanding your problem properly. I am on the #infinispan channel on FreeNode IRC. I have a feeling it would be a lot easier if we just spoke in real time and I can help you out where possible.
I think that if you have a CacheManager instance in each app with the same cache name (String) registered to each CM; your caches will be synchronised. This will work as long as long as you use the *same* configuration for each Cache instance.
But again, we could be barking up the wrong tree if I don't understand your problem properly. So, if you could find me on IRC would be great. I'm generally online from about 0900GMT up until 1800GMT roughly.