Text Entites and Docbook 5

I'm currently using 
Docbook 4.4 for my documents and I use externally resolved text entities quite a 
lot in my documents to make them portable and share a lot of information like 
product name and versions across all of the files for a particular library. In 
reading over the transition guide it looks as though entities are not as easily 
support using Docbook 5. Is this true and if so, what strategies are good for 
replacing external entities?

Cheers,

Eric 
J.