use environment variable in script assertion

In script assertion of a test step in SOAP UI, i am using

def currentLoc = context.expand( '${#Global#xsd_loc}' )
new File( currentLoc+'\\application.xsd' ).withReader

here xsd_loc is defined in Global Properties is preferences

But if i declare that property in envirinment variable in user variables and call it using #Env# then it don't work.

Please tell me how it will work