DOCBOOK-APPS: DSSSL getenv()

Hello, all!

I could not find the way to get environment variable
from DSSSL stylesheet in documentation. Is there ability/procedure to do it?
The gole is to define some output fonts and tags accordingly
with SP_ENCODING shell variable.

-- 
WBR, Oleg Amiton
Epsylon Technologies, R&D
http://www.demo.ru