[docbook] Entities in Docbook 5 rnc

[Kate . Wringe]

Hello,

I'm trying to upgrade our Docbook 4.2 DTD to Docbook 5 RNC.

In our version 4.2 DTD we included an external entity file that listed
the conditions that we used for condition attribute. Is there a way to 
link/include external files with the docbook 5 RNC?

For example, is it possible to have a file (eg., myconditions.ent) that 
defines an attribute such as (e.g,. db.iaconditions12.attributte) that
can be used in the definition of db.condition.attribute?

e.g., File myconditions.ent
db.myondition12.attribute =
 
    ## provides a standard place for application-specific effectivity
    attribute mycondition12 {"asajtools"
                        |"dbadmin"
                        |"mobilink"
                        |"programming"
                        |"sqlref"
                        |"sqlug"
                        |"uldotnet"
                        |"ulfoundations"
                        |"rsguide"}



E.g., I'd like to do something like the following in the Docbook 5 
customization file:
db.condition.attribute = 
    ## provides a standard place for application-specific effectivity
    attribute condition {mycondition12} 

If this is possible, how should I reference the myconditions.ent file  in 
the Docbook 5 RNC? 
And do I need to include a namespace reference in the myconditions.ent 
file?


Thank you,
Kate