Your subject line reads "Project Oriented"????

I'm not even entirely sure what you're saying.  If you take the time to
write in clear English, it's far more likely that someone will be able
to help.

Also, can you say what the context of these "service descriptors" is?  
The term isn't familiar to me.  A quick Google search turns up a number
of places where it is used (the OpenOffice API, writing Solaris
management modules, something called IceStorm, etc.)