Create caps presentation of phrase?

Platform: DocBook XML 4.2, DocBook XSL 1.69.1

Is it simple/possible to do something in the local XSL customization
layer, so that eg. <phrase role="caps">Some TeXt</phrase> can be
rendered as "SOME TEXT"?

It's a request from a DocBook user at work, that I don't know how to
answer. 

Thanx!


- Steinar